diff --git a/docs/ai-assistant-guide-extended.md b/docs/ai-assistant-guide-extended.md
index f6e11a62..3053111c 100644
--- a/docs/ai-assistant-guide-extended.md
+++ b/docs/ai-assistant-guide-extended.md
@@ -91,10 +91,11 @@ SQLite Database (Index)
 # List all projects
 projects = await list_memory_projects()
 
-# Response structure:
+# Response structure (each entry includes external_id you can pass as project_id):
 # [
 #   {
 #     "name": "main",
+#     "external_id": "550e8400-e29b-41d4-a716-446655440000",
 #     "path": "/Users/name/notes",
 #     "is_default": True,
 #     "note_count": 156,
@@ -102,6 +103,7 @@ projects = await list_memory_projects()
 #   },
 #   {
 #     "name": "work",
+#     "external_id": "9f86d081-884c-42a3-b5e3-1c0c5b4c8e52",
 #     "path": "/Users/name/work-notes",
 #     "is_default": False,
 #     "note_count": 89,
@@ -164,6 +166,44 @@ active_project = "main"
 results = await search_notes(query="topic", project=active_project)
 ```
 
+### `project` vs `project_id`
+
+Every project has two identifiers:
+
+- **`project`** — human-readable name (e.g., `"main"`). Easy to use, but can collide across cloud workspaces.
+- **`project_id`** — stable `external_id` UUID. Always unambiguous; takes precedence over `project` when both are passed.
+
+**When to prefer `project_id`:**
+
+1. **Cloud multi-workspace setups.** If the user belongs to more than one workspace (personal + organization, or several organizations) and the same project name might exist in more than one of them, pass `project_id` to route to the exact project. Without it, name resolution falls back to the default workspace, which may not be the one the user means.
+2. **After `list_memory_projects()`.** Once you have the `external_id`, prefer using it — it's the same number of characters in JSON and saves a name-resolution round-trip.
+3. **When persisting a project choice across a long session.** UUIDs are stable; names can be renamed.
+
+**When `project` (name) is fine:**
+
+- Local single-workspace setups (no collision risk).
+- One-off operations where the name is clearly visible to the user (e.g., quick `search_notes(project="main", ...)`).
+- The user explicitly references a project by name in their message.
+
+**Example — cloud multi-workspace pattern:**
+
+```python
+# Discover and pick the right project for this user
+projects = await list_memory_projects()
+target = next(p for p in projects if p["name"] == "research" and p["workspace"]["slug"] == "acme")
+
+# Use the UUID for all subsequent operations — no ambiguity
+await write_note(
+    title="Meeting Notes",
+    content="...",
+    folder="meetings",
+    project_id=target["external_id"],
+)
+results = await search_notes(query="kickoff", project_id=target["external_id"])
+```
+
+**Precedence rule:** When both are passed, `project_id` wins. This lets you safely supply `project="main"` for backward compatibility while still routing precisely with `project_id`.
+
 ### Cross-Project Operations
 
 **Some tools work across all projects when project parameter omitted:**
diff --git a/src/basic_memory/cli/commands/db.py b/src/basic_memory/cli/commands/db.py
index 793e548f..532bc9bb 100644
--- a/src/basic_memory/cli/commands/db.py
+++ b/src/basic_memory/cli/commands/db.py
@@ -99,9 +99,7 @@ def _abort_if_mcp_processes_alive() -> None:
     if not zombies:
         return
 
-    console.print(
-        "[red]Refusing to reset:[/red] basic-memory MCP processes are still running."
-    )
+    console.print("[red]Refusing to reset:[/red] basic-memory MCP processes are still running.")
     console.print(
         "[yellow]On macOS/Linux these would keep reading the deleted memory.db inode "
         "and return phantom search results (see #765).[/yellow]"
@@ -117,9 +115,7 @@ def _abort_if_mcp_processes_alive() -> None:
             "Where-Object {$_.CommandLine -like '*basic-memory*mcp*'}[/green]"
         )
     else:
-        console.print(
-            "  2. Verify nothing remains: [green]pgrep -fa 'basic-memory mcp'[/green]"
-        )
+        console.print("  2. Verify nothing remains: [green]pgrep -fa 'basic-memory mcp'[/green]")
     console.print("  3. Re-run [green]bm reset[/green].")
     raise typer.Exit(1)
 
diff --git a/src/basic_memory/cli/commands/tool.py b/src/basic_memory/cli/commands/tool.py
index 1dfdffea..0eb96aa4 100644
--- a/src/basic_memory/cli/commands/tool.py
+++ b/src/basic_memory/cli/commands/tool.py
@@ -62,9 +62,12 @@ def write_note(
             help="The project to write to. If not provided, the default project will be used."
         ),
     ] = None,
-    workspace: Annotated[
+    project_id: Annotated[
         Optional[str],
-        typer.Option(help="Cloud workspace tenant ID or unique name to route this request."),
+        typer.Option(
+            "--project-id",
+            help="Project external_id (UUID). Takes precedence over --project; use to disambiguate same-named projects across cloud workspaces.",
+        ),
     ] = None,
     local: bool = typer.Option(
         False, "--local", help="Force local API routing (ignore cloud mode)"
@@ -106,7 +109,7 @@ def write_note(
                     content=content,
                     directory=folder,
                     project=project,
-                    workspace=workspace,
+                    project_id=project_id,
                     tags=tags,
                     output_format="json",
                 )
@@ -132,9 +135,12 @@ def read_note(
         Optional[str],
         typer.Option(help="The project to use. If not provided, the default project will be used."),
     ] = None,
-    workspace: Annotated[
+    project_id: Annotated[
         Optional[str],
-        typer.Option(help="Cloud workspace tenant ID or unique name to route this request."),
+        typer.Option(
+            "--project-id",
+            help="Project external_id (UUID). Takes precedence over --project; use to disambiguate same-named projects across cloud workspaces.",
+        ),
     ] = None,
     local: bool = typer.Option(
         False, "--local", help="Force local API routing (ignore cloud mode)"
@@ -156,7 +162,7 @@ def read_note(
                 mcp_read_note(
                     identifier=identifier,
                     project=project,
-                    workspace=workspace,
+                    project_id=project_id,
                     include_frontmatter=include_frontmatter,
                     output_format="json",
                 )
@@ -195,9 +201,12 @@ def edit_note(
             help="The project to edit. If not provided, the default project will be used."
         ),
     ] = None,
-    workspace: Annotated[
+    project_id: Annotated[
         Optional[str],
-        typer.Option(help="Cloud workspace tenant ID or unique name to route this request."),
+        typer.Option(
+            "--project-id",
+            help="Project external_id (UUID). Takes precedence over --project; use to disambiguate same-named projects across cloud workspaces.",
+        ),
     ] = None,
     local: bool = typer.Option(
         False, "--local", help="Force local API routing (ignore cloud mode)"
@@ -222,7 +231,7 @@ def edit_note(
                     operation=operation,
                     content=content,
                     project=project,
-                    workspace=workspace,
+                    project_id=project_id,
                     section=section,
                     find_text=find_text,
                     expected_replacements=expected_replacements,
@@ -260,9 +269,12 @@ def build_context(
         Optional[str],
         typer.Option(help="The project to use. If not provided, the default project will be used."),
     ] = None,
-    workspace: Annotated[
+    project_id: Annotated[
         Optional[str],
-        typer.Option(help="Cloud workspace tenant ID or unique name to route this request."),
+        typer.Option(
+            "--project-id",
+            help="Project external_id (UUID). Takes precedence over --project; use to disambiguate same-named projects across cloud workspaces.",
+        ),
     ] = None,
     local: bool = typer.Option(
         False, "--local", help="Force local API routing (ignore cloud mode)"
@@ -284,7 +296,7 @@ def build_context(
                 mcp_build_context(
                     url=url,
                     project=project,
-                    workspace=workspace,
+                    project_id=project_id,
                     depth=depth,
                     timeframe=timeframe,
                     page=page,
@@ -317,9 +329,12 @@ def recent_activity(
         Optional[str],
         typer.Option(help="The project to use. If not provided, the default project will be used."),
     ] = None,
-    workspace: Annotated[
+    project_id: Annotated[
         Optional[str],
-        typer.Option(help="Cloud workspace tenant ID or unique name to route this request."),
+        typer.Option(
+            "--project-id",
+            help="Project external_id (UUID). Takes precedence over --project; use to disambiguate same-named projects across cloud workspaces.",
+        ),
     ] = None,
     local: bool = typer.Option(
         False, "--local", help="Force local API routing (ignore cloud mode)"
@@ -346,7 +361,7 @@ def recent_activity(
                     page=page,
                     page_size=page_size,
                     project=project,
-                    workspace=workspace,
+                    project_id=project_id,
                     output_format="json",
                 )
             )
@@ -408,9 +423,12 @@ def search_notes(
         Optional[str],
         typer.Option(help="The project to use. If not provided, the default project will be used."),
     ] = None,
-    workspace: Annotated[
+    project_id: Annotated[
         Optional[str],
-        typer.Option(help="Cloud workspace tenant ID or unique name to route this request."),
+        typer.Option(
+            "--project-id",
+            help="Project external_id (UUID). Takes precedence over --project; use to disambiguate same-named projects across cloud workspaces.",
+        ),
     ] = None,
     local: bool = typer.Option(
         False, "--local", help="Force local API routing (ignore cloud mode)"
@@ -482,7 +500,7 @@ def search_notes(
                 mcp_search(
                     query=query or None,
                     project=project,
-                    workspace=workspace,
+                    project_id=project_id,
                     search_type=search_type,
                     output_format="json",
                     page=page,
@@ -592,9 +610,12 @@ def schema_validate(
         Optional[str],
         typer.Option(help="The project to use. If not provided, the default project will be used."),
     ] = None,
-    workspace: Annotated[
+    project_id: Annotated[
         Optional[str],
-        typer.Option(help="Cloud workspace tenant ID or unique name to route this request."),
+        typer.Option(
+            "--project-id",
+            help="Project external_id (UUID). Takes precedence over --project; use to disambiguate same-named projects across cloud workspaces.",
+        ),
     ] = None,
     local: bool = typer.Option(
         False, "--local", help="Force local API routing (ignore cloud mode)"
@@ -629,7 +650,7 @@ def schema_validate(
                     note_type=note_type,
                     identifier=identifier,
                     project=project,
-                    workspace=workspace,
+                    project_id=project_id,
                     output_format="json",
                 )
             )
@@ -660,9 +681,12 @@ def schema_infer(
         Optional[str],
         typer.Option(help="The project to use. If not provided, the default project will be used."),
     ] = None,
-    workspace: Annotated[
+    project_id: Annotated[
         Optional[str],
-        typer.Option(help="Cloud workspace tenant ID or unique name to route this request."),
+        typer.Option(
+            "--project-id",
+            help="Project external_id (UUID). Takes precedence over --project; use to disambiguate same-named projects across cloud workspaces.",
+        ),
     ] = None,
     local: bool = typer.Option(
         False, "--local", help="Force local API routing (ignore cloud mode)"
@@ -686,7 +710,7 @@ def schema_infer(
                     note_type=note_type,
                     threshold=threshold,
                     project=project,
-                    workspace=workspace,
+                    project_id=project_id,
                     output_format="json",
                 )
             )
@@ -714,9 +738,12 @@ def schema_diff(
         Optional[str],
         typer.Option(help="The project to use. If not provided, the default project will be used."),
     ] = None,
-    workspace: Annotated[
+    project_id: Annotated[
         Optional[str],
-        typer.Option(help="Cloud workspace tenant ID or unique name to route this request."),
+        typer.Option(
+            "--project-id",
+            help="Project external_id (UUID). Takes precedence over --project; use to disambiguate same-named projects across cloud workspaces.",
+        ),
     ] = None,
     local: bool = typer.Option(
         False, "--local", help="Force local API routing (ignore cloud mode)"
@@ -738,7 +765,7 @@ def schema_diff(
                 mcp_schema_diff(
                     note_type=note_type,
                     project=project,
-                    workspace=workspace,
+                    project_id=project_id,
                     output_format="json",
                 )
             )
diff --git a/src/basic_memory/mcp/project_context.py b/src/basic_memory/mcp/project_context.py
index 792b1608..81cf32b1 100644
--- a/src/basic_memory/mcp/project_context.py
+++ b/src/basic_memory/mcp/project_context.py
@@ -10,8 +10,9 @@
 
 import asyncio
 from contextlib import asynccontextmanager
-from dataclasses import dataclass
+from dataclasses import dataclass, field
 from typing import AsyncIterator, Awaitable, Callable, Optional, List, Tuple, cast
+from uuid import UUID
 
 from httpx import AsyncClient
 from httpx._types import (
@@ -52,11 +53,12 @@ def qualified_name(self) -> str:
 
 @dataclass(frozen=True)
 class WorkspaceProjectIndex:
-    """Session-local cloud project lookup index keyed by project permalink."""
+    """Session-local cloud project lookup index keyed by project permalink and external_id."""
 
     workspaces: tuple[WorkspaceInfo, ...]
     entries: tuple[WorkspaceProjectEntry, ...]
     entries_by_permalink: dict[str, tuple[WorkspaceProjectEntry, ...]]
+    entries_by_external_id: dict[str, WorkspaceProjectEntry] = field(default_factory=dict)
     failed_workspaces: tuple[WorkspaceInfo, ...] = ()
 
 
@@ -351,10 +353,12 @@ def _build_workspace_project_index(
     *,
     failed_workspaces: tuple[WorkspaceInfo, ...] = (),
 ) -> WorkspaceProjectIndex:
-    """Build the permalink lookup table for workspace-project entries."""
+    """Build the permalink and external_id lookup tables for workspace-project entries."""
     grouped: dict[str, list[WorkspaceProjectEntry]] = {}
+    by_external_id: dict[str, WorkspaceProjectEntry] = {}
     for entry in entries:
         grouped.setdefault(entry.project.permalink, []).append(entry)
+        by_external_id[entry.project.external_id] = entry
 
     return WorkspaceProjectIndex(
         workspaces=workspaces,
@@ -363,6 +367,7 @@ def _build_workspace_project_index(
             permalink: tuple(items)
             for permalink, items in sorted(grouped.items(), key=lambda item: item[0])
         },
+        entries_by_external_id=by_external_id,
         failed_workspaces=failed_workspaces,
     )
 
@@ -549,8 +554,20 @@ async def resolve_workspace_project_identifier(
     project: str,
     context: Optional[Context] = None,
 ) -> WorkspaceProjectEntry:
-    """Resolve an unqualified or ``<workspace>/<project>`` cloud project identifier."""
+    """Resolve a project by external_id (UUID), qualified name, or unqualified name."""
     index = await _ensure_workspace_project_index(context=context)
+
+    # Fast path: direct lookup by external_id when the identifier is a UUID
+    # Canonicalize via str(UUID(...)) so uppercase, brace-wrapped, or urn:uuid forms
+    # all hash to the same lowercase-hyphenated key as the stored external_ids.
+    try:
+        canonical_external_id = str(UUID(project))
+        entry = index.entries_by_external_id.get(canonical_external_id)
+        if entry:
+            return entry
+    except ValueError:
+        pass
+
     workspace_slug, project_identifier = _split_qualified_project_identifier(project)
     project_permalink = generate_permalink(project_identifier)
 
@@ -617,6 +634,11 @@ async def resolve_workspace_project_identifier(
             return cached_matches[0]
 
     if len(matches) > 1:
+        # Prefer the project in the default workspace when name is ambiguous
+        default_match = next((entry for entry in matches if entry.workspace.is_default), None)
+        if default_match:
+            return default_match
+
         choices = _format_qualified_choices(matches)
         details = "\n".join(
             f"- {entry.workspace.name} ({entry.workspace.slug}): {entry.qualified_name}"
@@ -956,8 +978,8 @@ def detect_project_from_url_prefix(identifier: str, config: BasicMemoryConfig) -
 @asynccontextmanager
 async def get_project_client(
     project: Optional[str] = None,
-    workspace: Optional[str] = None,
     context: Optional[Context] = None,
+    project_id: Optional[str] = None,
 ) -> AsyncIterator[Tuple[AsyncClient, ProjectItem]]:
     """Resolve project, create correctly-routed client, and validate project.
 
@@ -972,16 +994,13 @@ async def get_project_client(
     3. Cloud project mode → resolve project through workspace/project index
     4. Otherwise → local ASGI client
 
-    Workspace resolution priority (when cloud routing):
-    1. Explicit ``workspace`` parameter
-    2. Per-project ``workspace_id`` from config
-    3. Qualified project identifier (``<workspace-slug>/<project>``)
-    4. Workspace/project index lookup with collision detection
-
     Args:
-        project: Optional explicit project parameter
-        workspace: Optional cloud workspace selector (tenant_id or unique name)
+        project: Optional explicit project parameter (name or permalink)
         context: Optional FastMCP context for caching
+        project_id: Optional project external_id (UUID). When provided, takes
+            precedence over ``project`` and disambiguates the project across
+            workspaces. Use this when the same project name exists in multiple
+            cloud workspaces.
 
     Yields:
         Tuple of (client, active_project)
@@ -998,8 +1017,12 @@ async def get_project_client(
         is_factory_mode,
     )
 
+    # When project_id (UUID) is provided, prefer it as the resolution identifier.
+    # external_id is unambiguous across workspaces; project name can collide.
+    project_identifier = project_id if project_id else project
+
     # Step 1: Resolve project name from config (no network call)
-    resolved_project = await resolve_project_parameter(project, context=context)
+    resolved_project = await resolve_project_parameter(project_identifier, context=context)
     config = ConfigManager().config
     factory_mode = is_factory_mode()
     explicit_cloud_routing = _explicit_routing() and not _force_local_mode()
@@ -1050,19 +1073,14 @@ async def get_project_client(
     project_entry = config.projects.get(resolved_project)
     project_mode = config.get_project_mode(resolved_project)
 
-    # Trigger: workspace provided for a local project (without explicit --cloud)
-    # Why: workspace selection is a cloud routing concern only
-    # Outcome: fail fast with a deterministic guidance message
-    if (
-        not factory_mode
-        and project_mode != ProjectMode.CLOUD
-        and workspace is not None
-        and not _explicit_routing()
-    ):
-        raise ValueError(
-            f"Workspace '{workspace}' cannot be used with local project '{resolved_project}'. "
-            "Workspace selection is only supported for cloud-mode projects."
-        )
+    # Trigger: identifier is a UUID (project_id) but local config keys by name only
+    # Why: get_project_mode defaults to CLOUD for unknown identifiers; a UUID is
+    #   never registered in local config, so it would always falsely route cloud
+    # Outcome: in pure local mode, treat UUID identifiers as local routing; cloud
+    #   discovery still happens when factory/explicit/credentials are present
+    cloud_available = factory_mode or explicit_cloud_routing or has_cloud_credentials(config)
+    if project_id and not cloud_available:
+        project_mode = ProjectMode.LOCAL
 
     if factory_mode or project_mode == ProjectMode.CLOUD or explicit_cloud_routing:
         route_mode = "factory" if factory_mode else "cloud_proxy"
@@ -1070,17 +1088,8 @@ async def get_project_client(
         workspace_id: str
         project_for_api = _unqualified_project_identifier(resolved_project)
 
-        # Trigger: a script or config entry pins the tenant explicitly
-        # Why: explicit tenant configuration remains the escape hatch during migration
-        # Outcome: route to that workspace, but validate the project name inside it
-        if workspace is not None:
-            active_ws = await resolve_workspace_parameter(workspace=workspace, context=context)
-            workspace_id = active_ws.tenant_id
-        elif project_entry and project_entry.workspace_id:
-            # Trigger: the local project config already stores the cloud tenant id.
-            # Why: routing can send that id directly; requiring workspace discovery here
-            #   would turn a control-plane listing outage into a project routing failure.
-            # Outcome: preserve project-scoped routing even when discovery is unavailable.
+        if project_entry and project_entry.workspace_id:
+            # Per-project config stores the cloud tenant id directly
             workspace_id = project_entry.workspace_id
         else:
             resolved_entry = cloud_default_entry
@@ -1120,6 +1129,12 @@ async def get_project_client(
         route_mode=route_mode,
     ):
         logger.debug("Using default local ASGI routing for project client")
-        async with get_client(project_name=resolved_project) as client:
+        # Trigger: UUID identifiers won't match name-keyed local config entries.
+        # Why: get_client(project_name=<uuid>) would consult get_project_mode and
+        #   default to CLOUD for unknown identifiers, breaking pure-local routing.
+        # Outcome: skip per-project routing for UUIDs — local mode routes every
+        #   project through the same ASGI client; the API resolves the UUID below.
+        client_kwargs = {} if project_id else {"project_name": resolved_project}
+        async with get_client(**client_kwargs) as client:
             active_project = await get_active_project(client, resolved_project, context)
             yield client, active_project
diff --git a/src/basic_memory/mcp/resources/ai_assistant_guide.md b/src/basic_memory/mcp/resources/ai_assistant_guide.md
index 009c7561..f2eb5df0 100644
--- a/src/basic_memory/mcp/resources/ai_assistant_guide.md
+++ b/src/basic_memory/mcp/resources/ai_assistant_guide.md
@@ -18,13 +18,15 @@ Basic Memory creates a semantic knowledge graph from markdown files. Focus on bu
 
 **Resolution priority:**
 1. CLI constraint: `BASIC_MEMORY_MCP_PROJECT` env var (highest priority)
-2. Explicit parameter: `project="name"` in tool calls
+2. Explicit parameter: `project_id="<uuid>"` (preferred when known) or `project="name"` in tool calls
 3. Default project: `default_project` in config (fallback)
 
+**`project` vs `project_id`:** Every project has a stable `external_id` (UUID) returned by `list_memory_projects()`. Pass it as `project_id=...` to address a project unambiguously — required when the same project name exists in multiple cloud workspaces. For local single-project setups, the `project` name is fine.
+
 ### Quick Setup Check
 
 ```python
-# Discover projects
+# Discover projects (each entry includes external_id you can pass as project_id)
 projects = await list_memory_projects()
 ```
 
@@ -169,6 +171,14 @@ await write_note(
 **Multi-project users:**
 - Always specify project explicitly in tool calls
 
+**Cloud multi-workspace users:** project names can collide across workspaces. After calling `list_memory_projects()`, prefer the project's `external_id` via `project_id=...` for any subsequent tool calls — it routes to the exact project regardless of name collisions. The `project` name parameter falls back to the default workspace on ambiguity, which may not be what you want.
+
+```python
+# Cloud / multi-workspace: prefer project_id (UUID) once you've discovered it
+projects = await list_memory_projects()
+results = await search_notes(query="auth", project_id=projects[0]["external_id"])
+```
+
 **Discovery:**
 ```python
 # Start with discovery
diff --git a/src/basic_memory/mcp/tools/build_context.py b/src/basic_memory/mcp/tools/build_context.py
index c29942bf..0d90684f 100644
--- a/src/basic_memory/mcp/tools/build_context.py
+++ b/src/basic_memory/mcp/tools/build_context.py
@@ -139,7 +139,7 @@ async def build_context(
         Field(validation_alias=AliasChoices("url", "uri", "memory_url")),
     ],
     project: Optional[str] = None,
-    workspace: Optional[str] = None,
+    project_id: Optional[str] = None,
     depth: str | int | None = 1,
     timeframe: Annotated[
         Optional[TimeFrame],
@@ -179,6 +179,9 @@ async def build_context(
     Args:
         project: Project name to build context from. Optional - server will resolve using hierarchy.
                 If unknown, use list_memory_projects() to discover available projects.
+        project_id: Project external_id (UUID). Prefer this over `project` when known —
+                it routes to the exact project regardless of name collisions across cloud
+                workspaces. Takes precedence over `project`. Get from list_memory_projects().
         url: memory:// URI pointing to discussion content (e.g. memory://specs/search)
         depth: How many relation hops to traverse (1-3 recommended for performance)
         timeframe: How far back to look. Supports natural language like "2 days ago", "last week"
@@ -228,7 +231,7 @@ async def build_context(
         entrypoint="mcp",
         tool_name="build_context",
         requested_project=project,
-        workspace_id=workspace,
+        requested_project_id=project_id,
         depth=depth or 1,
         timeframe=timeframe,
         page=page,
@@ -237,7 +240,10 @@ async def build_context(
         output_format=output_format,
         is_memory_url=str(url).startswith("memory://"),
     ):
-        async with get_project_client(project, workspace, context) as (client, active_project):
+        async with get_project_client(project, context=context, project_id=project_id) as (
+            client,
+            active_project,
+        ):
             logger.info(
                 f"MCP tool call tool=build_context project={active_project.name} "
                 f"url={url} depth={depth} timeframe={timeframe} output_format={output_format}"
diff --git a/src/basic_memory/mcp/tools/canvas.py b/src/basic_memory/mcp/tools/canvas.py
index 52ebd825..ca5b85cf 100644
--- a/src/basic_memory/mcp/tools/canvas.py
+++ b/src/basic_memory/mcp/tools/canvas.py
@@ -29,7 +29,7 @@ async def canvas(
         Field(validation_alias=AliasChoices("directory", "folder", "dir", "path")),
     ],
     project: Optional[str] = None,
-    workspace: Optional[str] = None,
+    project_id: Optional[str] = None,
     context: Context | None = None,
 ) -> str:
     """Create an Obsidian canvas file with the provided nodes and edges.
@@ -46,6 +46,9 @@ async def canvas(
     Args:
         project: Project name to create canvas in. Optional - server will resolve using hierarchy.
                 If unknown, use list_memory_projects() to discover available projects.
+        project_id: Project external_id (UUID). Prefer this over `project` when known —
+                it routes to the exact project regardless of name collisions across cloud
+                workspaces. Takes precedence over `project`. Get from list_memory_projects().
         nodes: List of node objects following JSON Canvas 1.0 spec
         edges: List of edge objects following JSON Canvas 1.0 spec
         title: The title of the canvas (will be saved as title.canvas)
@@ -100,7 +103,10 @@ async def canvas(
     Raises:
         ToolError: If project doesn't exist or directory path is invalid
     """
-    async with get_project_client(project, workspace, context) as (client, active_project):
+    async with get_project_client(project, context=context, project_id=project_id) as (
+        client,
+        active_project,
+    ):
         # Ensure path has .canvas extension
         file_title = title if title.endswith(".canvas") else f"{title}.canvas"
         file_path = f"{directory}/{file_title}"
diff --git a/src/basic_memory/mcp/tools/delete_note.py b/src/basic_memory/mcp/tools/delete_note.py
index a368e148..9a5d7a21 100644
--- a/src/basic_memory/mcp/tools/delete_note.py
+++ b/src/basic_memory/mcp/tools/delete_note.py
@@ -159,7 +159,7 @@ async def delete_note(
         Field(default=False, validation_alias=AliasChoices("is_directory", "is_dir")),
     ] = False,
     project: Optional[str] = None,
-    workspace: Optional[str] = None,
+    project_id: Optional[str] = None,
     output_format: Literal["text", "json"] = "text",
     context: Context | None = None,
 ) -> bool | str | dict:
@@ -183,6 +183,9 @@ async def delete_note(
                      (without file extensions). Defaults to False.
         project: Project name to delete from. Optional - server will resolve using hierarchy.
                 If unknown, use list_memory_projects() to discover available projects.
+        project_id: Project external_id (UUID). Prefer this over `project` when known —
+                it routes to the exact project regardless of name collisions across cloud
+                workspaces. Takes precedence over `project`. Get from list_memory_projects().
         output_format: "text" preserves existing behavior (bool/string). "json"
             returns machine-readable deletion metadata.
         context: Optional FastMCP context for performance caching.
@@ -237,7 +240,10 @@ async def delete_note(
         if detected:
             project = detected
 
-    async with get_project_client(project, workspace, context) as (client, active_project):
+    async with get_project_client(project, context=context, project_id=project_id) as (
+        client,
+        active_project,
+    ):
         logger.debug(
             f"Deleting {'directory' if is_directory else 'note'}: {identifier} in project: {active_project.name}"
         )
diff --git a/src/basic_memory/mcp/tools/edit_note.py b/src/basic_memory/mcp/tools/edit_note.py
index 45e16ddf..cd107d70 100644
--- a/src/basic_memory/mcp/tools/edit_note.py
+++ b/src/basic_memory/mcp/tools/edit_note.py
@@ -176,13 +176,11 @@ async def edit_note(
     content: Annotated[
         str,
         Field(
-            validation_alias=AliasChoices(
-                "content", "new_content", "replacement", "replace_with"
-            )
+            validation_alias=AliasChoices("content", "new_content", "replacement", "replace_with")
         ),
     ],
     project: Optional[str] = None,
-    workspace: Optional[str] = None,
+    project_id: Optional[str] = None,
     # Section/heading naming varies across tools; accept the descriptive forms.
     section: Annotated[
         Optional[str],
@@ -197,9 +195,7 @@ async def edit_note(
         Optional[str],
         Field(
             default=None,
-            validation_alias=AliasChoices(
-                "find_text", "find", "old_text", "old_content", "search"
-            ),
+            validation_alias=AliasChoices("find_text", "find", "old_text", "old_content", "search"),
         ),
     ] = None,
     expected_replacements: Optional[int] = None,
@@ -228,6 +224,9 @@ async def edit_note(
         content: The content to add or use for replacement
         project: Project name to edit in. Optional - server will resolve using hierarchy.
                 If unknown, use list_memory_projects() to discover available projects.
+        project_id: Project external_id (UUID). Prefer this over `project` when known —
+                it routes to the exact project regardless of name collisions across cloud
+                workspaces. Takes precedence over `project`. Get from list_memory_projects().
         section: For replace_section operation - the markdown header to replace content under (e.g., "## Notes", "### Implementation")
         find_text: For find_replace operation - the text to find and replace
         expected_replacements: For find_replace operation - the expected number of replacements (validation will fail if actual doesn't match)
@@ -303,14 +302,17 @@ async def edit_note(
         entrypoint="mcp",
         tool_name="edit_note",
         requested_project=project,
-        workspace_id=workspace,
+        requested_project_id=project_id,
         edit_operation=operation,
         output_format=output_format,
         has_section=bool(section),
         has_find_text=bool(find_text),
         expected_replacements=effective_replacements,
     ):
-        async with get_project_client(project, workspace, context) as (client, active_project):
+        async with get_project_client(project, context=context, project_id=project_id) as (
+            client,
+            active_project,
+        ):
             logger.info(
                 f"MCP tool call tool=edit_note project={active_project.name} "
                 f"identifier={identifier} operation={operation} output_format={output_format}"
diff --git a/src/basic_memory/mcp/tools/list_directory.py b/src/basic_memory/mcp/tools/list_directory.py
index 0ec3e6d8..22ca5dcf 100644
--- a/src/basic_memory/mcp/tools/list_directory.py
+++ b/src/basic_memory/mcp/tools/list_directory.py
@@ -32,7 +32,7 @@ async def list_directory(
         ),
     ] = None,
     project: Optional[str] = None,
-    workspace: Optional[str] = None,
+    project_id: Optional[str] = None,
     context: Context | None = None,
 ) -> str:
     """List directory contents from the knowledge base with optional filtering.
@@ -50,6 +50,9 @@ async def list_directory(
                        Examples: "*.md", "*meeting*", "project_*"
         project: Project name to list directory from. Optional - server will resolve using hierarchy.
                 If unknown, use list_memory_projects() to discover available projects.
+        project_id: Project external_id (UUID). Prefer this over `project` when known —
+                it routes to the exact project regardless of name collisions across cloud
+                workspaces. Takes precedence over `project`. Get from list_memory_projects().
         context: Optional FastMCP context for performance caching.
 
     Returns:
@@ -77,7 +80,10 @@ async def list_directory(
     Raises:
         ToolError: If project doesn't exist or directory path is invalid
     """
-    async with get_project_client(project, workspace, context) as (client, active_project):
+    async with get_project_client(project, context=context, project_id=project_id) as (
+        client,
+        active_project,
+    ):
         logger.debug(
             f"Listing directory '{dir_name}' in project {project} with depth={depth}, glob='{file_name_glob}'"
         )
diff --git a/src/basic_memory/mcp/tools/move_note.py b/src/basic_memory/mcp/tools/move_note.py
index fbf17dd3..5b140024 100644
--- a/src/basic_memory/mcp/tools/move_note.py
+++ b/src/basic_memory/mcp/tools/move_note.py
@@ -371,7 +371,7 @@ async def move_note(
         Field(default=False, validation_alias=AliasChoices("is_directory", "is_dir")),
     ] = False,
     project: Optional[str] = None,
-    workspace: Optional[str] = None,
+    project_id: Optional[str] = None,
     output_format: Literal["text", "json"] = "text",
     context: Context | None = None,
 ) -> str | dict:
@@ -396,6 +396,9 @@ async def move_note(
                      (without file extensions). Defaults to False.
         project: Project name to move within. Optional - server will resolve using hierarchy.
                 If unknown, use list_memory_projects() to discover available projects.
+        project_id: Project external_id (UUID). Prefer this over `project` when known —
+                it routes to the exact project regardless of name collisions across cloud
+                workspaces. Takes precedence over `project`. Get from list_memory_projects().
         output_format: "text" returns existing markdown guidance/success text. "json"
             returns machine-readable move metadata.
         context: Optional FastMCP context for performance caching.
@@ -495,7 +498,10 @@ async def move_note(
                 "error": "DESTINATION_FOLDER_NOT_FOR_DIRECTORIES",
             }
         return f"# Move Failed - Invalid Parameters\n\n{error_msg}"
-    async with get_project_client(project, workspace, context) as (client, active_project):
+    async with get_project_client(project, context=context, project_id=project_id) as (
+        client,
+        active_project,
+    ):
         destination_target = destination_folder or destination_path
         logger.info(
             f"MCP tool call tool=move_note project={active_project.name} "
diff --git a/src/basic_memory/mcp/tools/project_management.py b/src/basic_memory/mcp/tools/project_management.py
index 79c18c9d..44800538 100644
--- a/src/basic_memory/mcp/tools/project_management.py
+++ b/src/basic_memory/mcp/tools/project_management.py
@@ -11,11 +11,10 @@
 from loguru import logger
 
 from basic_memory.config import ConfigManager, has_cloud_credentials
-from basic_memory.mcp.async_client import get_client, get_cloud_proxy_client, is_factory_mode
+from basic_memory.mcp.async_client import get_client, is_factory_mode
 from basic_memory.mcp.project_context import (
     WorkspaceProjectEntry,
     ensure_workspace_project_index,
-    resolve_workspace_parameter,
 )
 from basic_memory.mcp.server import mcp
 from basic_memory.schemas.project_info import ProjectInfoRequest, ProjectItem, ProjectList
@@ -25,36 +24,6 @@
 # --- Helpers for dual-fetch + merge ---
 
 
-async def _fetch_cloud_projects(
-    workspace: str | None = None,
-    context: Context | None = None,
-) -> ProjectList | None:
-    """Fetch projects from the cloud API, returning None on failure.
-
-    Logs warnings on failure so list_memory_projects can fall back to local-only
-    results. Project-scoped routing does not use this listing fallback.
-    """
-    try:
-        from basic_memory.mcp.clients import ProjectClient
-
-        async with get_cloud_proxy_client(workspace=workspace) as cloud_client:
-            cloud_project_client = ProjectClient(cloud_client)
-            cloud_list = await cloud_project_client.list_projects()
-        if context:  # pragma: no cover
-            await context.info(f"Discovered {len(cloud_list.projects)} cloud projects")
-        return cloud_list
-    except Exception as exc:
-        logger.warning(
-            f"Cloud project discovery failed while listing projects; "
-            f"showing local-only project list: {exc}"
-        )
-        if context:  # pragma: no cover
-            await context.info(
-                "Cloud project discovery failed while listing projects; showing local projects only"
-            )
-        return None
-
-
 def _merge_projects(
     local_list: ProjectList | None,
     cloud_list: ProjectList | None,
@@ -126,9 +95,13 @@ def _merge_projects(
         ws_type = cloud_workspace_type if cloud_proj else None
         ws_tenant_id = cloud_workspace_tenant_id if cloud_proj else None
 
+        proj = cloud_proj or local_proj
+        external_id = proj.external_id if proj else None
+
         merged.append(
             {
                 "name": name,
+                "external_id": external_id,
                 "path": path,
                 "local_path": local_path,
                 "cloud_path": cloud_path,
@@ -184,6 +157,7 @@ def _merge_workspace_projects(
         merged.append(
             {
                 "name": cloud_proj.name,
+                "external_id": cloud_proj.external_id,
                 "path": local_path or cloud_path,
                 "local_path": local_path,
                 "cloud_path": cloud_path,
@@ -207,6 +181,7 @@ def _merge_workspace_projects(
             merged.append(
                 {
                     "name": project.name,
+                    "external_id": project.external_id,
                     "path": project.path,
                     "local_path": project.path,
                     "cloud_path": None,
@@ -248,9 +223,9 @@ def _format_project_list_text(merged: list[dict]) -> str:
         name = project["name"]
         label = f"{display_name} ({name})" if display_name else name
         source = project["source"]
-        qualified_name = project.get("qualified_name")
-        qualified_suffix = f" [{qualified_name}]" if qualified_name else ""
-        result += f"- {label} ({source}){qualified_suffix}\n"
+        external_id = project.get("external_id", "")
+        id_suffix = f" [{external_id}]" if external_id else ""
+        result += f"- {label} ({source}){id_suffix}\n"
 
     result += "\n" + "─" * 40 + "\n"
     result += "Next: Ask which project to use for this session.\n"
@@ -282,7 +257,6 @@ def _format_project_list_json(
 )
 async def list_memory_projects(
     output_format: Literal["text", "json"] = "text",
-    workspace: str | None = None,
     context: Context | None = None,
 ) -> str | dict:
     """List all available projects with their status.
@@ -290,11 +264,14 @@ async def list_memory_projects(
     Shows projects from both local and cloud sources when cloud credentials
     are available, merging by permalink to give a unified view.
 
+    Each project entry includes an `external_id` (UUID). Pass that value as the
+    `project_id` parameter on other tools to address a specific project
+    unambiguously across cloud workspaces — useful when the same project name
+    exists in more than one workspace.
+
     Args:
         output_format: "text" returns the existing human-readable project list.
             "json" returns structured project metadata.
-        workspace: Cloud workspace name or tenant_id. Falls back to
-            config.default_workspace when not specified.
         context: Optional FastMCP context for progress/status logging.
     """
     if context:  # pragma: no cover
@@ -309,7 +286,7 @@ async def list_memory_projects(
     # Why: there is no local ASGI server; the factory IS the cloud source
     # Outcome: single fetch, projects reported as source="cloud" with workspace metadata
     if is_factory_mode():
-        async with get_client(workspace=workspace) as client:
+        async with get_client() as client:
             project_client = ProjectClient(client)
             project_list = await project_client.list_projects()
 
@@ -324,13 +301,7 @@ async def list_memory_projects(
 
             workspaces = await get_available_workspaces(context)
             if workspaces:
-                # In factory mode the user is authenticated to a single workspace;
-                # use the explicit workspace param or fall back to the first available.
-                matched = None
-                if workspace:
-                    matched = next((ws for ws in workspaces if ws.tenant_id == workspace), None)
-                if matched is None:
-                    matched = workspaces[0]
+                matched = workspaces[0]
                 cloud_ws_name = matched.name
                 cloud_ws_type = matched.workspace_type
                 cloud_ws_tenant_id = matched.tenant_id
@@ -372,42 +343,19 @@ async def list_memory_projects(
     cloud_ws_is_default = False
     config = ConfigManager().config
     if has_cloud_credentials(config):
-        if workspace:
-            try:
-                active_workspace = await resolve_workspace_parameter(workspace, context)
-            except Exception as exc:
-                logger.warning(
-                    f"Cloud workspace discovery failed while listing projects for "
-                    f"workspace '{workspace}'; trying direct workspace routing before "
-                    f"falling back to local-only project list: {exc}"
-                )
-                if context:  # pragma: no cover
-                    await context.info(
-                        "Cloud workspace discovery failed while listing projects; "
-                        "trying direct workspace routing"
-                    )
-                cloud_list = await _fetch_cloud_projects(workspace, context)
-            else:
-                cloud_list = await _fetch_cloud_projects(active_workspace.tenant_id, context)
-                cloud_ws_name = active_workspace.name
-                cloud_ws_type = active_workspace.workspace_type
-                cloud_ws_tenant_id = active_workspace.tenant_id
-                cloud_ws_slug = active_workspace.slug
-                cloud_ws_is_default = active_workspace.is_default
-        else:
-            try:
-                workspace_index = await ensure_workspace_project_index(context=context)
-                cloud_entries = workspace_index.entries
-            except Exception as exc:
-                logger.warning(
-                    f"Cloud workspace project index discovery failed while listing projects; "
-                    f"showing local-only project list: {exc}"
+        try:
+            workspace_index = await ensure_workspace_project_index(context=context)
+            cloud_entries = workspace_index.entries
+        except Exception as exc:
+            logger.warning(
+                f"Cloud workspace project index discovery failed while listing projects; "
+                f"showing local-only project list: {exc}"
+            )
+            if context:  # pragma: no cover
+                await context.info(
+                    "Cloud workspace project discovery failed while listing projects; "
+                    "showing local projects only"
                 )
-                if context:  # pragma: no cover
-                    await context.info(
-                        "Cloud workspace project discovery failed while listing projects; "
-                        "showing local projects only"
-                    )
 
     if cloud_entries:
         merged = _merge_workspace_projects(local_list, cloud_entries)
@@ -515,6 +463,7 @@ async def create_memory_project(
             if output_format == "json":
                 return {
                     "name": existing_match.name,
+                    "external_id": existing_match.external_id,
                     "path": existing_match.path,
                     "is_default": is_default,
                     "created": False,
@@ -524,6 +473,7 @@ async def create_memory_project(
                 f"✓ Project already exists: {existing_match.name}\n\n"
                 f"Project Details:\n"
                 f"• Name: {existing_match.name}\n"
+                f"• External ID: {existing_match.external_id}\n"
                 f"• Path: {existing_match.path}\n"
                 f"{'• Set as default project\n' if is_default else ''}"
                 "\nProject is already available for use in tool calls.\n"
@@ -538,6 +488,7 @@ async def create_memory_project(
             new_project = status_response.new_project
             return {
                 "name": new_project.name if new_project else project_name,
+                "external_id": new_project.external_id if new_project else None,
                 "path": new_project.path if new_project else project_path,
                 "is_default": bool(
                     (new_project.is_default if new_project else False) or set_default
@@ -551,6 +502,7 @@ async def create_memory_project(
         if status_response.new_project:
             result += "Project Details:\n"
             result += f"• Name: {status_response.new_project.name}\n"
+            result += f"• External ID: {status_response.new_project.external_id}\n"
             result += f"• Path: {status_response.new_project.path}\n"
 
             if set_default:
diff --git a/src/basic_memory/mcp/tools/read_content.py b/src/basic_memory/mcp/tools/read_content.py
index 269beb11..2c9d1831 100644
--- a/src/basic_memory/mcp/tools/read_content.py
+++ b/src/basic_memory/mcp/tools/read_content.py
@@ -164,7 +164,7 @@ async def read_content(
         Field(validation_alias=AliasChoices("path", "file_path", "filepath", "file")),
     ],
     project: Optional[str] = None,
-    workspace: Optional[str] = None,
+    project_id: Optional[str] = None,
     context: Context | None = None,
 ) -> dict:
     """Read a file's raw content by path or permalink.
@@ -185,6 +185,9 @@ async def read_content(
             - A permalink (docs/example)
         project: Project name to read from. Optional - server will resolve using hierarchy.
                 If unknown, use list_memory_projects() to discover available projects.
+        project_id: Project external_id (UUID). Prefer this over `project` when known —
+                it routes to the exact project regardless of name collisions across cloud
+                workspaces. Takes precedence over `project`. Get from list_memory_projects().
         context: Optional FastMCP context for performance caching.
 
     Returns:
@@ -222,9 +225,14 @@ async def read_content(
 
     logger.info(f"MCP tool call tool=read_content project={project} path={path}")
 
-    async with get_project_client(project, workspace, context) as (client, active_project):
-        # Resolve path with project-prefix awareness for memory:// URLs
-        _, url, _ = await resolve_project_and_path(client, path, project, context)
+    async with get_project_client(project, context=context, project_id=project_id) as (
+        client,
+        active_project,
+    ):
+        # Resolve path with project-prefix awareness for memory:// URLs.
+        # Use active_project.name so resolution stays consistent when project_id
+        # was used or `project` was wrong/ambiguous (matches the cached resolution).
+        _, url, _ = await resolve_project_and_path(client, path, active_project.name, context)
 
         # Validate path to prevent path traversal attacks
         # For memory:// URLs, validate the extracted path (not the raw URL which
diff --git a/src/basic_memory/mcp/tools/read_note.py b/src/basic_memory/mcp/tools/read_note.py
index 0c22a0b6..461450e2 100644
--- a/src/basic_memory/mcp/tools/read_note.py
+++ b/src/basic_memory/mcp/tools/read_note.py
@@ -70,7 +70,7 @@ def _parse_opening_frontmatter(content: str) -> tuple[str, dict | None]:
 async def read_note(
     identifier: str,
     project: Optional[str] = None,
-    workspace: Optional[str] = None,
+    project_id: Optional[str] = None,
     output_format: Literal["text", "json"] = "text",
     include_frontmatter: bool = False,
     context: Context | None = None,
@@ -94,6 +94,9 @@ async def read_note(
         project: Project name to read from. Optional - server will resolve using the
                 hierarchy above. If unknown, use list_memory_projects() to discover
                 available projects.
+        project_id: Project external_id (UUID). Prefer this over `project` when known —
+                it routes to the exact project regardless of name collisions across cloud
+                workspaces. Takes precedence over `project`. Get from list_memory_projects().
         identifier: The title or permalink of the note to read
                    Can be a full memory:// URL, a permalink, a title, or search text
         output_format: "text" returns markdown content or guidance text.
@@ -138,13 +141,21 @@ async def read_note(
         entrypoint="mcp",
         tool_name="read_note",
         requested_project=project,
-        workspace_id=workspace,
+        requested_project_id=project_id,
         output_format=output_format,
         include_frontmatter=include_frontmatter,
     ):
-        async with get_project_client(project, workspace, context) as (client, active_project):
-            # Resolve identifier with project-prefix awareness for memory:// URLs
-            _, entity_path, _ = await resolve_project_and_path(client, identifier, project, context)
+        async with get_project_client(project, context=context, project_id=project_id) as (
+            client,
+            active_project,
+        ):
+            # Resolve identifier with project-prefix awareness for memory:// URLs.
+            # Pass active_project.name (the canonical resolved name) rather than the
+            # original `project` arg so the inner get_active_project cache hits even
+            # when project_id was used or `project` was wrong/ambiguous.
+            _, entity_path, _ = await resolve_project_and_path(
+                client, identifier, active_project.name, context
+            )
 
             # Validate identifier to prevent path traversal attacks
             # For memory:// URLs, validate the extracted path (not the raw URL which
@@ -235,10 +246,14 @@ async def _search_candidates(
                 # Why: search_notes applies the same memory:// normalization and tool-level
                 #      query handling as the rest of MCP routing, which raw client calls skip.
                 # Outcome: unresolved memory URLs still fall back through normalized search.
+                # Pass project_id (external_id UUID) so the workspace selection from the
+                # outer get_project_client() is preserved across the inner re-resolution.
+                # Without this, project names that collide across workspaces could re-resolve
+                # to a different tenant via the default-workspace fallback (CLI/context=None).
                 search_type = "title" if title_only else "text"
                 response = await search_notes(
                     project=active_project.name,
-                    workspace=workspace,
+                    project_id=active_project.external_id,
                     query=identifier_text,
                     search_type=search_type,
                     output_format="json",
diff --git a/src/basic_memory/mcp/tools/recent_activity.py b/src/basic_memory/mcp/tools/recent_activity.py
index 969dde8b..2de3a80f 100644
--- a/src/basic_memory/mcp/tools/recent_activity.py
+++ b/src/basic_memory/mcp/tools/recent_activity.py
@@ -62,7 +62,7 @@ async def recent_activity(
         Field(default=10, validation_alias=AliasChoices("page_size", "limit", "per_page")),
     ] = 10,
     project: Optional[str] = None,
-    workspace: Optional[str] = None,
+    project_id: Optional[str] = None,
     output_format: Literal["text", "json"] = "text",
     context: Context | None = None,
 ) -> str | list[dict]:
@@ -104,6 +104,9 @@ async def recent_activity(
         project: Project name to query. Optional - server will resolve using the
                 hierarchy above. If unknown, use list_memory_projects() to discover
                 available projects.
+        project_id: Project external_id (UUID). Prefer this over `project` when known —
+                it routes to the exact project regardless of name collisions across cloud
+                workspaces. Takes precedence over `project`. Get from list_memory_projects().
         output_format: "text" returns human-readable summary text. "json" returns
             a flat list of recent items.
         context: Optional FastMCP context for performance caching.
@@ -179,9 +182,14 @@ async def recent_activity(
     if "type" not in params:
         params["type"] = [SearchItemType.ENTITY.value]
 
-    # Resolve project parameter using the three-tier hierarchy
-    # allow_discovery=True enables Discovery Mode, so a project is not required
-    resolved_project = await resolve_project_parameter(project, allow_discovery=True)
+    # Resolve project parameter using the three-tier hierarchy.
+    # allow_discovery=True enables Discovery Mode, so a project is not required.
+    # project_id (UUID) takes precedence over project name — without this fallback,
+    # callers passing only project_id would fall into Discovery Mode.
+    effective_identifier = project_id if project_id else project
+    resolved_project = await resolve_project_parameter(
+        effective_identifier, allow_discovery=True
+    )
 
     if resolved_project is None:
         # Discovery Mode: Get activity across all projects
@@ -296,7 +304,9 @@ async def recent_activity(
             f"Getting recent activity from project {resolved_project}: type={type}, depth={depth}, timeframe={timeframe}"
         )
 
-        async with get_project_client(resolved_project, workspace, context) as (
+        async with get_project_client(
+            resolved_project, context=context, project_id=project_id
+        ) as (
             client,
             active_project,
         ):
diff --git a/src/basic_memory/mcp/tools/schema.py b/src/basic_memory/mcp/tools/schema.py
index b24663d1..c3c3f999 100644
--- a/src/basic_memory/mcp/tools/schema.py
+++ b/src/basic_memory/mcp/tools/schema.py
@@ -211,7 +211,7 @@ async def schema_validate(
     note_type: Optional[str] = None,
     identifier: Optional[str] = None,
     project: Optional[str] = None,
-    workspace: Optional[str] = None,
+    project_id: Optional[str] = None,
     output_format: Literal["text", "json"] = "text",
     context: Context | None = None,
 ) -> ValidationReport | str | dict:
@@ -236,6 +236,9 @@ async def schema_validate(
         identifier: Specific note to validate (permalink, title, or path).
             If provided, validates only this note.
         project: Project name. Optional -- server will resolve.
+        project_id: Project external_id (UUID). Prefer this over `project` when known —
+                it routes to the exact project regardless of name collisions across cloud
+                workspaces. Takes precedence over `project`. Get from list_memory_projects().
         context: Optional FastMCP context for performance caching.
 
     Returns:
@@ -251,7 +254,10 @@ async def schema_validate(
         # Validate in a specific project
         schema_validate(note_type="person", project="my-research")
     """
-    async with get_project_client(project, workspace, context) as (client, active_project):
+    async with get_project_client(project, context=context, project_id=project_id) as (
+        client,
+        active_project,
+    ):
         logger.info(
             f"MCP tool call tool=schema_validate project={active_project.name} "
             f"note_type={note_type} identifier={identifier}"
@@ -318,7 +324,7 @@ async def schema_infer(
     note_type: str,
     threshold: float = 0.25,
     project: Optional[str] = None,
-    workspace: Optional[str] = None,
+    project_id: Optional[str] = None,
     output_format: Literal["text", "json"] = "text",
     context: Context | None = None,
 ) -> str | dict:
@@ -342,6 +348,9 @@ async def schema_infer(
         threshold: Minimum frequency (0-1) for a field to be suggested as optional.
             Default 0.25 (25%). Fields above 95% become required.
         project: Project name. Optional -- server will resolve.
+        project_id: Project external_id (UUID). Prefer this over `project` when known —
+                it routes to the exact project regardless of name collisions across cloud
+                workspaces. Takes precedence over `project`. Get from list_memory_projects().
         context: Optional FastMCP context for performance caching.
 
     Returns:
@@ -357,7 +366,10 @@ async def schema_infer(
         # Infer in a specific project
         schema_infer("person", project="my-research")
     """
-    async with get_project_client(project, workspace, context) as (client, active_project):
+    async with get_project_client(project, context=context, project_id=project_id) as (
+        client,
+        active_project,
+    ):
         logger.info(
             f"MCP tool call tool=schema_infer project={active_project.name} "
             f"note_type={note_type} threshold={threshold}"
@@ -432,7 +444,7 @@ async def schema_infer(
 async def schema_diff(
     note_type: str,
     project: Optional[str] = None,
-    workspace: Optional[str] = None,
+    project_id: Optional[str] = None,
     output_format: Literal["text", "json"] = "text",
     context: Context | None = None,
 ) -> str | dict:
@@ -453,6 +465,9 @@ async def schema_diff(
     Args:
         note_type: The note type to check for drift (e.g., "person").
         project: Project name. Optional -- server will resolve.
+        project_id: Project external_id (UUID). Prefer this over `project` when known —
+                it routes to the exact project regardless of name collisions across cloud
+                workspaces. Takes precedence over `project`. Get from list_memory_projects().
         context: Optional FastMCP context for performance caching.
 
     Returns:
@@ -466,7 +481,10 @@ async def schema_diff(
         # Check drift in a specific project
         schema_diff("person", project="my-research")
     """
-    async with get_project_client(project, workspace, context) as (client, active_project):
+    async with get_project_client(project, context=context, project_id=project_id) as (
+        client,
+        active_project,
+    ):
         logger.info(
             f"MCP tool call tool=schema_diff project={active_project.name} note_type={note_type}"
         )
diff --git a/src/basic_memory/mcp/tools/search.py b/src/basic_memory/mcp/tools/search.py
index 974be6ef..5b17f047 100644
--- a/src/basic_memory/mcp/tools/search.py
+++ b/src/basic_memory/mcp/tools/search.py
@@ -308,7 +308,7 @@ async def search_notes(
         Field(default=None, validation_alias=AliasChoices("query", "q", "search", "text")),
     ] = None,
     project: Optional[str] = None,
-    workspace: Optional[str] = None,
+    project_id: Optional[str] = None,
     # `offset` is intentionally NOT aliased to `page`: offset is item-indexed
     # (skip N items) while page is 1-indexed page-number. Direct aliasing would
     # silently return the wrong slice.
@@ -359,9 +359,7 @@ async def search_notes(
         Optional[float],
         Field(
             default=None,
-            validation_alias=AliasChoices(
-                "min_similarity", "threshold", "similarity_threshold"
-            ),
+            validation_alias=AliasChoices("min_similarity", "threshold", "similarity_threshold"),
         ),
     ] = None,
     context: Context | None = None,
@@ -447,6 +445,9 @@ async def search_notes(
               Omit or pass None for filter-only searches using metadata_filters, tags, or status.
         project: Project name to search in. Optional - server will resolve using hierarchy.
                 If unknown, use list_memory_projects() to discover available projects.
+        project_id: Project external_id (UUID). Prefer this over `project` when known —
+                it routes to the exact project regardless of name collisions across cloud
+                workspaces. Takes precedence over `project`. Get from list_memory_projects().
         page: The page number of results to return (default 1)
         page_size: The number of results to return per page (default 10)
         search_type: Type of search to perform, one of:
@@ -561,7 +562,7 @@ async def search_notes(
         entrypoint="mcp",
         tool_name="search_notes",
         requested_project=project,
-        workspace_id=workspace,
+        requested_project_id=project_id,
         search_type=search_type or "default",
         output_format=output_format,
         page=page,
@@ -575,12 +576,17 @@ async def search_notes(
         has_tags_filter=bool(tags),
         has_status_filter=bool(status),
     ):
-        async with get_project_client(project, workspace, context) as (client, active_project):
-            # Handle memory:// URLs by resolving to permalink search
+        async with get_project_client(project, context=context, project_id=project_id) as (
+            client,
+            active_project,
+        ):
+            # Handle memory:// URLs by resolving to permalink search.
+            # Use active_project.name so resolution hits the cached active project
+            # when project_id was used or `project` was wrong/ambiguous.
             is_memory_url = False
             if query is not None:
                 _, resolved_query, is_memory_url = await resolve_project_and_path(
-                    client, query, project, context
+                    client, query, active_project.name, context
                 )
                 if is_memory_url:
                     query = resolved_query
diff --git a/src/basic_memory/mcp/tools/ui_sdk.py b/src/basic_memory/mcp/tools/ui_sdk.py
index 82da3bc7..b70f7d79 100644
--- a/src/basic_memory/mcp/tools/ui_sdk.py
+++ b/src/basic_memory/mcp/tools/ui_sdk.py
@@ -25,6 +25,7 @@ def _text_block(message: str) -> List[ContentBlock]:
 async def search_notes_ui(
     query: str,
     project: Optional[str] = None,
+    project_id: Optional[str] = None,
     page: int = 1,
     page_size: int = 10,
     search_type: Optional[str] = None,
@@ -49,6 +50,7 @@ async def search_notes_ui(
     result = await search_notes(
         query=query,
         project=project,
+        project_id=project_id,
         page=page,
         page_size=page_size,
         search_type=search_type,
@@ -97,12 +99,14 @@ async def search_notes_ui(
 async def read_note_ui(
     identifier: str,
     project: Optional[str] = None,
+    project_id: Optional[str] = None,
     context: Context | None = None,
 ) -> List[ContentBlock]:
     """Return a note preview UI as an embedded MCP-UI resource."""
     content = await read_note(
         identifier=identifier,
         project=project,
+        project_id=project_id,
         output_format="text",
         context=context,
     )
diff --git a/src/basic_memory/mcp/tools/view_note.py b/src/basic_memory/mcp/tools/view_note.py
index 129f3e03..534ec791 100644
--- a/src/basic_memory/mcp/tools/view_note.py
+++ b/src/basic_memory/mcp/tools/view_note.py
@@ -17,7 +17,7 @@
 async def view_note(
     identifier: str,
     project: Optional[str] = None,
-    workspace: Optional[str] = None,
+    project_id: Optional[str] = None,
     context: Context | None = None,
 ) -> str:
     """View a markdown note as a formatted artifact.
@@ -30,6 +30,9 @@ async def view_note(
         identifier: The title or permalink of the note to view
         project: Project name to read from. Optional - server will resolve using hierarchy.
                 If unknown, use list_memory_projects() to discover available projects.
+        project_id: Project external_id (UUID). Prefer this over `project` when known —
+                it routes to the exact project regardless of name collisions across cloud
+                workspaces. Takes precedence over `project`. Get from list_memory_projects().
         context: Optional FastMCP context for performance caching.
 
     Returns:
@@ -56,7 +59,7 @@ async def view_note(
         await read_note(
             identifier=identifier,
             project=project,
-            workspace=workspace,
+            project_id=project_id,
             context=context,
         )
     )
diff --git a/src/basic_memory/mcp/tools/write_note.py b/src/basic_memory/mcp/tools/write_note.py
index 734cb8d9..cb8bd172 100644
--- a/src/basic_memory/mcp/tools/write_note.py
+++ b/src/basic_memory/mcp/tools/write_note.py
@@ -31,7 +31,7 @@ async def write_note(
         Field(validation_alias=AliasChoices("directory", "folder", "dir", "path")),
     ],
     project: Optional[str] = None,
-    workspace: Optional[str] = None,
+    project_id: Optional[str] = None,
     tags: list[str] | str | None = None,
     note_type: str = "note",
     metadata: Annotated[dict | None, BeforeValidator(coerce_dict)] = None,
@@ -82,6 +82,9 @@ async def write_note(
         project: Project name to write to. Optional - server will resolve using the
                 hierarchy above. If unknown, use list_memory_projects() to discover
                 available projects.
+        project_id: Project external_id (UUID). Prefer this over `project` when known —
+                it routes to the exact project regardless of name collisions across cloud
+                workspaces. Takes precedence over `project`. Get from list_memory_projects().
         tags: Tags to categorize the note. Can be a list of strings, a comma-separated string, or None.
               Note: If passing from external MCP clients, use a string format (e.g. "tag1,tag2,tag3")
         note_type: Type of note to create (stored in frontmatter). Defaults to "note".
@@ -162,12 +165,15 @@ async def write_note(
         entrypoint="mcp",
         tool_name="write_note",
         requested_project=project,
-        workspace_id=workspace,
+        requested_project_id=project_id,
         note_type=note_type,
         overwrite=effective_overwrite,
         output_format=output_format,
     ):
-        async with get_project_client(project, workspace, context) as (client, active_project):
+        async with get_project_client(project, context=context, project_id=project_id) as (
+            client,
+            active_project,
+        ):
             logger.info(
                 f"MCP tool call tool=write_note project={active_project.name} directory={directory}, title={title}, tags={tags}"
             )
diff --git a/src/basic_memory/repository/sqlite_search_repository.py b/src/basic_memory/repository/sqlite_search_repository.py
index df9db73a..7d11874e 100644
--- a/src/basic_memory/repository/sqlite_search_repository.py
+++ b/src/basic_memory/repository/sqlite_search_repository.py
@@ -107,8 +107,7 @@ async def init_search_index(self):
                 await self._ensure_vector_tables()
             except SemanticDependenciesMissingError as exc:
                 logger.warning(
-                    f"Semantic search disabled: {exc}. "
-                    "Falling back to keyword-only search."
+                    f"Semantic search disabled: {exc}. Falling back to keyword-only search."
                 )
                 self._semantic_enabled = False
 
diff --git a/test-int/mcp/test_param_aliases_integration.py b/test-int/mcp/test_param_aliases_integration.py
index a359cb6b..d3500235 100644
--- a/test-int/mcp/test_param_aliases_integration.py
+++ b/test-int/mcp/test_param_aliases_integration.py
@@ -489,7 +489,17 @@ async def test_aliases_not_advertised_in_schema(mcp_server, app):
             ),
             "search_notes": (
                 ["query", "page", "page_size", "note_types", "after_date", "min_similarity"],
-                ["q", "search", "offset", "limit", "note_type", "types", "since", "after", "threshold"],
+                [
+                    "q",
+                    "search",
+                    "offset",
+                    "limit",
+                    "note_type",
+                    "types",
+                    "since",
+                    "after",
+                    "threshold",
+                ],
             ),
             "recent_activity": (
                 ["type", "timeframe", "page", "page_size"],
diff --git a/test-int/mcp/test_read_note_integration.py b/test-int/mcp/test_read_note_integration.py
index bb4b4f8c..2e1ceb6b 100644
--- a/test-int/mcp/test_read_note_integration.py
+++ b/test-int/mcp/test_read_note_integration.py
@@ -100,3 +100,71 @@ async def test_read_note_underscored_folder_by_permalink(mcp_server, app, test_p
         assert "# Example Note" in result_text
         assert "This is a test note in an underscored folder." in result_text
         assert f"{test_project.name}/archive/articles/example-note" in result_text  # permalink
+
+
+@pytest.mark.asyncio
+async def test_read_note_by_project_id(mcp_server, app, test_project):
+    """Read a note by passing project_id (UUID) instead of project name.
+
+    Verifies the project_id parameter routes through get_project_client correctly
+    in pure local mode (no cloud creds), where get_project_mode() would otherwise
+    default unknown identifiers to CLOUD and break routing.
+    """
+
+    async with Client(mcp_server) as client:
+        await client.call_tool(
+            "write_note",
+            {
+                "project": test_project.name,
+                "title": "By ID Note",
+                "directory": "test",
+                "content": "# By ID Note\n\nLooked up by external_id.",
+            },
+        )
+
+        # Read by external_id (UUID) instead of project name
+        read_result = await client.call_tool(
+            "read_note",
+            {
+                "project_id": test_project.external_id,
+                "identifier": "By ID Note",
+            },
+        )
+
+        assert len(read_result.content) == 1
+        assert read_result.content[0].type == "text"
+        result_text = read_result.content[0].text
+        assert "# By ID Note" in result_text
+        assert "Looked up by external_id." in result_text
+
+
+@pytest.mark.asyncio
+async def test_read_note_project_id_takes_precedence_over_name(mcp_server, app, test_project):
+    """When project_id is passed alongside a wrong project name, project_id wins."""
+
+    async with Client(mcp_server) as client:
+        await client.call_tool(
+            "write_note",
+            {
+                "project": test_project.name,
+                "title": "Precedence Note",
+                "directory": "test",
+                "content": "# Precedence Note\n\nproject_id wins.",
+            },
+        )
+
+        # Pass an obviously-wrong project name alongside the correct project_id.
+        # If project_id takes precedence (as documented), the read still succeeds.
+        read_result = await client.call_tool(
+            "read_note",
+            {
+                "project": "this-project-does-not-exist",
+                "project_id": test_project.external_id,
+                "identifier": "Precedence Note",
+            },
+        )
+
+        assert len(read_result.content) == 1
+        result_text = read_result.content[0].text
+        assert "# Precedence Note" in result_text
+        assert "project_id wins." in result_text
diff --git a/tests/cli/test_cli_tool_json_output.py b/tests/cli/test_cli_tool_json_output.py
index 2b7502c8..d5e5e183 100644
--- a/tests/cli/test_cli_tool_json_output.py
+++ b/tests/cli/test_cli_tool_json_output.py
@@ -113,6 +113,38 @@ def test_write_note_json_output(mock_mcp_write):
     assert mock_mcp_write.call_args.kwargs["output_format"] == "json"
 
 
+@patch(
+    "basic_memory.cli.commands.tool.mcp_write_note",
+    new_callable=AsyncMock,
+    return_value=WRITE_NOTE_RESULT,
+)
+def test_write_note_project_id_passthrough(mock_mcp_write):
+    """--project-id forwards to the MCP tool's project_id parameter.
+
+    Regression: removing --workspace without exposing --project-id left CLI
+    callers unable to disambiguate same-named projects across cloud workspaces.
+    """
+    uuid = "11111111-1111-1111-1111-111111111111"
+    result = runner.invoke(
+        cli_app,
+        [
+            "tool",
+            "write-note",
+            "--title",
+            "Test Note",
+            "--folder",
+            "notes",
+            "--content",
+            "hello",
+            "--project-id",
+            uuid,
+        ],
+    )
+
+    assert result.exit_code == 0, f"CLI failed: {result.output}"
+    assert mock_mcp_write.call_args.kwargs["project_id"] == uuid
+
+
 @patch(
     "basic_memory.cli.commands.tool.mcp_write_note",
     new_callable=AsyncMock,
@@ -167,22 +199,6 @@ def test_read_note_json_output(mock_mcp_read):
     assert mock_mcp_read.call_args.kwargs["output_format"] == "json"
 
 
-@patch(
-    "basic_memory.cli.commands.tool.mcp_read_note",
-    new_callable=AsyncMock,
-    return_value=READ_NOTE_RESULT,
-)
-def test_read_note_workspace_passthrough(mock_mcp_read):
-    """read-note --workspace passes workspace through to the MCP tool call."""
-    result = runner.invoke(
-        cli_app,
-        ["tool", "read-note", "test-note", "--workspace", "tenant-123"],
-    )
-
-    assert result.exit_code == 0, f"CLI failed: {result.output}"
-    assert mock_mcp_read.call_args.kwargs["workspace"] == "tenant-123"
-
-
 @patch(
     "basic_memory.cli.commands.tool.mcp_read_note",
     new_callable=AsyncMock,
diff --git a/tests/markdown/test_markdown_plugins.py b/tests/markdown/test_markdown_plugins.py
index 0fd3593c..12b917f8 100644
--- a/tests/markdown/test_markdown_plugins.py
+++ b/tests/markdown/test_markdown_plugins.py
@@ -189,8 +189,7 @@ def test_observation_skips_obsidian_callouts():
         t.meta.get("observation")
         for t in tokens
         if t.type == "inline" and t.meta and t.meta.get("observation")
-        if t.meta["observation"]["category"]
-        and t.meta["observation"]["category"].startswith("!")
+        if t.meta["observation"]["category"] and t.meta["observation"]["category"].startswith("!")
     ]
     assert callout_observations == [], (
         f"Obsidian callouts should not produce observations, got: {callout_observations}"
diff --git a/tests/mcp/test_project_context.py b/tests/mcp/test_project_context.py
index de1e5d8d..56b47152 100644
--- a/tests/mcp/test_project_context.py
+++ b/tests/mcp/test_project_context.py
@@ -606,8 +606,10 @@ async def fake_index(context=None):
     assert resolved.workspace.slug == "acme"
     assert resolved.project.external_id == "acme-project-id"
 
-    with pytest.raises(ValueError, match="Use: personal/meeting-notes or acme/meeting-notes"):
-        await resolve_workspace_project_identifier("meeting-notes")
+    # Ambiguous name resolves to the default workspace (personal)
+    resolved = await resolve_workspace_project_identifier("meeting-notes")
+    assert resolved.workspace.slug == "personal"
+    assert resolved.project.external_id == "personal-project-id"
 
 
 @pytest.mark.asyncio
@@ -663,6 +665,180 @@ async def fake_index(context=None):
     assert resolved.project.external_id == "acme-project-id"
 
 
+@pytest.mark.asyncio
+async def test_resolve_workspace_project_identifier_resolves_by_external_id(monkeypatch):
+    """Direct lookup by external_id (UUID) bypasses name/permalink resolution."""
+    import basic_memory.mcp.project_context as project_context
+    from basic_memory.mcp.project_context import (
+        WorkspaceProjectEntry,
+        _build_workspace_project_index,
+        resolve_workspace_project_identifier,
+    )
+
+    personal = _workspace(
+        tenant_id="personal-tenant",
+        workspace_type="personal",
+        slug="personal",
+        name="Personal",
+        role="owner",
+        is_default=True,
+    )
+    acme = _workspace(
+        tenant_id="acme-tenant",
+        workspace_type="organization",
+        slug="acme",
+        name="Acme",
+        role="editor",
+    )
+    # Same project name in two workspaces — UUID lookup must pick the right one
+    # without falling back to default-workspace ambiguity handling.
+    entries = (
+        WorkspaceProjectEntry(
+            workspace=personal,
+            project=_project(
+                "Meeting Notes", id=1, external_id="11111111-1111-1111-1111-111111111111"
+            ),
+        ),
+        WorkspaceProjectEntry(
+            workspace=acme,
+            project=_project(
+                "Meeting Notes", id=2, external_id="22222222-2222-2222-2222-222222222222"
+            ),
+        ),
+    )
+    index = _build_workspace_project_index((personal, acme), entries)
+
+    async def fake_index(context=None):
+        return index
+
+    monkeypatch.setattr(project_context, "_ensure_workspace_project_index", fake_index)
+
+    resolved = await resolve_workspace_project_identifier(
+        "22222222-2222-2222-2222-222222222222"
+    )
+    assert resolved.workspace.slug == "acme"
+    assert resolved.project.external_id == "22222222-2222-2222-2222-222222222222"
+
+
+@pytest.mark.asyncio
+async def test_resolve_workspace_project_identifier_normalizes_uuid_forms(monkeypatch):
+    """Uppercase, brace-wrapped, and urn:uuid forms canonicalize before lookup."""
+    import basic_memory.mcp.project_context as project_context
+    from basic_memory.mcp.project_context import (
+        WorkspaceProjectEntry,
+        _build_workspace_project_index,
+        resolve_workspace_project_identifier,
+    )
+
+    workspace = _workspace(
+        tenant_id="personal-tenant",
+        workspace_type="personal",
+        slug="personal",
+        name="Personal",
+        role="owner",
+        is_default=True,
+    )
+    canonical_uuid = "33333333-3333-3333-3333-333333333333"
+    entries = (
+        WorkspaceProjectEntry(
+            workspace=workspace,
+            project=_project("Meeting Notes", id=1, external_id=canonical_uuid),
+        ),
+    )
+    index = _build_workspace_project_index((workspace,), entries)
+
+    async def fake_index(context=None):
+        return index
+
+    monkeypatch.setattr(project_context, "_ensure_workspace_project_index", fake_index)
+
+    # Each variant should canonicalize to the same lowercase-hyphenated form
+    for variant in (
+        canonical_uuid.upper(),
+        f"{{{canonical_uuid}}}",
+        f"urn:uuid:{canonical_uuid}",
+        canonical_uuid.replace("-", ""),
+    ):
+        resolved = await resolve_workspace_project_identifier(variant)
+        assert resolved.project.external_id == canonical_uuid, (
+            f"variant {variant!r} did not resolve to canonical UUID"
+        )
+
+
+@pytest.mark.asyncio
+async def test_get_project_client_with_project_id_routes_locally_without_cloud(
+    config_manager, monkeypatch
+):
+    """A UUID project_id in pure local mode must not trigger cloud routing.
+
+    Regression: get_project_mode() defaults unknown identifiers to CLOUD because the
+    local config keys by name. UUIDs are never registered locally, so without the
+    fix below, passing project_id would falsely route through the cloud client and
+    error out for users with no cloud credentials.
+    """
+    import basic_memory.mcp.project_context as project_context
+
+    # Pure local mode: no cloud creds, no factory mode, no explicit cloud routing
+    config = config_manager.load_config()
+    config.cloud_api_key = None
+    config_manager.save_config(config)
+
+    monkeypatch.setattr(project_context, "has_cloud_credentials", lambda _config: False)
+
+    captured: dict[str, object] = {}
+
+    @asynccontextmanager
+    async def fake_get_client(**kwargs) -> AsyncIterator[object]:
+        captured["get_client_kwargs"] = kwargs
+        yield object()
+
+    async def fake_get_active_project(client, project, context, headers=None):
+        captured["validated_project"] = project
+        return _project("Local Project", id=99, external_id=project)
+
+    monkeypatch.setattr("basic_memory.mcp.async_client.get_client", fake_get_client)
+    monkeypatch.setattr("basic_memory.mcp.async_client.is_factory_mode", lambda: False)
+    monkeypatch.setattr("basic_memory.mcp.async_client._explicit_routing", lambda: False)
+    monkeypatch.setattr("basic_memory.mcp.async_client._force_local_mode", lambda: False)
+    monkeypatch.setattr(project_context, "get_active_project", fake_get_active_project)
+
+    canonical_uuid = "55555555-5555-5555-5555-555555555555"
+    async with project_context.get_project_client(project_id=canonical_uuid) as (_, active):
+        assert active.external_id == canonical_uuid
+
+    # When project_id is set, get_client must be called WITHOUT project_name so the
+    # ASGI fallback is selected (not the per-project cloud-by-default path).
+    assert captured["get_client_kwargs"] == {}
+    assert captured["validated_project"] == canonical_uuid
+
+
+@pytest.mark.asyncio
+async def test_get_project_client_prefers_project_id_over_project_name(monkeypatch):
+    """When both project and project_id are passed, the UUID takes precedence."""
+    import basic_memory.mcp.project_context as project_context
+
+    # Capture which identifier flows into resolution, then short-circuit before
+    # the rest of the routing chain runs (avoids real network calls).
+    captured: dict[str, str | None] = {}
+    sentinel = RuntimeError("stop after resolution")
+
+    async def fake_resolve(project=None, *, allow_discovery=True, context=None):
+        captured["project"] = project
+        raise sentinel
+
+    monkeypatch.setattr(project_context, "resolve_project_parameter", fake_resolve)
+
+    canonical_uuid = "44444444-4444-4444-4444-444444444444"
+    with pytest.raises(RuntimeError, match="stop after resolution"):
+        async with project_context.get_project_client(
+            project="ambiguous-name",
+            project_id=canonical_uuid,
+        ):
+            pass
+
+    assert captured["project"] == canonical_uuid
+
+
 @pytest.mark.asyncio
 async def test_resolve_project_parameter_uses_cached_active_project_before_api_default_lookup(
     config_manager, monkeypatch
@@ -828,24 +1004,6 @@ async def fake_resolve_project_parameter(project=None, **kwargs):
     assert is_memory_url is True
 
 
-@pytest.mark.asyncio
-async def test_get_project_client_rejects_workspace_for_local_project(config_manager):
-    from basic_memory.mcp.project_context import get_project_client
-    from basic_memory.config import ProjectEntry
-
-    # Register "main" as a LOCAL project so get_project_mode returns LOCAL
-    config = config_manager.load_config()
-    (config_manager.config_dir.parent / "main").mkdir(parents=True, exist_ok=True)
-    config.projects["main"] = ProjectEntry(path=str(config_manager.config_dir.parent / "main"))
-    config_manager.save_config(config)
-
-    with pytest.raises(
-        ValueError, match="Workspace 'tenant-123' cannot be used with local project"
-    ):
-        async with get_project_client(project="main", workspace="tenant-123"):
-            pass
-
-
 class TestDetectProjectFromUrlPrefix:
     """Test detect_project_from_url_prefix for URL-based project detection."""
 
diff --git a/tests/mcp/test_tool_contracts.py b/tests/mcp/test_tool_contracts.py
index 55576ed7..6327a2ab 100644
--- a/tests/mcp/test_tool_contracts.py
+++ b/tests/mcp/test_tool_contracts.py
@@ -13,7 +13,7 @@
     "build_context": [
         "url",
         "project",
-        "workspace",
+        "project_id",
         "depth",
         "timeframe",
         "page",
@@ -21,25 +21,25 @@
         "max_related",
         "output_format",
     ],
-    "canvas": ["nodes", "edges", "title", "directory", "project", "workspace"],
+    "canvas": ["nodes", "edges", "title", "directory", "project", "project_id"],
     "cloud_info": [],
     "create_memory_project": ["project_name", "project_path", "set_default", "output_format"],
-    "delete_note": ["identifier", "is_directory", "project", "workspace", "output_format"],
+    "delete_note": ["identifier", "is_directory", "project", "project_id", "output_format"],
     "delete_project": ["project_name"],
     "edit_note": [
         "identifier",
         "operation",
         "content",
         "project",
-        "workspace",
+        "project_id",
         "section",
         "find_text",
         "expected_replacements",
         "output_format",
     ],
     "fetch": ["id"],
-    "list_directory": ["dir_name", "depth", "file_name_glob", "project", "workspace"],
-    "list_memory_projects": ["output_format", "workspace"],
+    "list_directory": ["dir_name", "depth", "file_name_glob", "project", "project_id"],
+    "list_memory_projects": ["output_format"],
     "list_workspaces": ["output_format"],
     "move_note": [
         "identifier",
@@ -47,14 +47,14 @@
         "destination_folder",
         "is_directory",
         "project",
-        "workspace",
+        "project_id",
         "output_format",
     ],
-    "read_content": ["path", "project", "workspace"],
+    "read_content": ["path", "project", "project_id"],
     "read_note": [
         "identifier",
         "project",
-        "workspace",
+        "project_id",
         "output_format",
         "include_frontmatter",
     ],
@@ -66,17 +66,17 @@
         "page",
         "page_size",
         "project",
-        "workspace",
+        "project_id",
         "output_format",
     ],
-    "schema_diff": ["note_type", "project", "workspace", "output_format"],
-    "schema_infer": ["note_type", "threshold", "project", "workspace", "output_format"],
-    "schema_validate": ["note_type", "identifier", "project", "workspace", "output_format"],
+    "schema_diff": ["note_type", "project", "project_id", "output_format"],
+    "schema_infer": ["note_type", "threshold", "project", "project_id", "output_format"],
+    "schema_validate": ["note_type", "identifier", "project", "project_id", "output_format"],
     "search": ["query"],
     "search_notes": [
         "query",
         "project",
-        "workspace",
+        "project_id",
         "page",
         "page_size",
         "search_type",
@@ -89,13 +89,13 @@
         "status",
         "min_similarity",
     ],
-    "view_note": ["identifier", "project", "workspace"],
+    "view_note": ["identifier", "project", "project_id"],
     "write_note": [
         "title",
         "content",
         "directory",
         "project",
-        "workspace",
+        "project_id",
         "tags",
         "note_type",
         "metadata",
diff --git a/tests/mcp/test_tool_json_output_modes.py b/tests/mcp/test_tool_json_output_modes.py
index aa5e5ca5..069534b5 100644
--- a/tests/mcp/test_tool_json_output_modes.py
+++ b/tests/mcp/test_tool_json_output_modes.py
@@ -215,6 +215,9 @@ async def test_list_and_create_project_text_and_json_modes(app, test_project, tm
     )
     assert isinstance(create_text, str)
     assert "mode-create-project" in create_text
+    # external_id should appear in the human-readable output too, so users see
+    # the UUID without re-listing projects.
+    assert "External ID:" in create_text
 
     create_json_again = await create_memory_project(
         project_name=project_name,
@@ -227,6 +230,24 @@ async def test_list_and_create_project_text_and_json_modes(app, test_project, tm
     assert Path(create_json_again["path"]) == Path(project_path)
     assert create_json_again["created"] is False
     assert create_json_again["already_exists"] is True
+    # external_id (UUID) must be present so callers can immediately use it as
+    # project_id in subsequent tool calls without a list_memory_projects() round-trip.
+    assert isinstance(create_json_again["external_id"], str)
+    assert len(create_json_again["external_id"]) > 0
+
+    # Verify create-new JSON path also returns external_id (not just already-exists).
+    new_project_name = "mode-create-fresh"
+    new_project_path = str(tmp_path.parent / (tmp_path.name + "-projects") / "mode-create-fresh")
+    create_json_new = await create_memory_project(
+        project_name=new_project_name,
+        project_path=new_project_path,
+        output_format="json",
+    )
+    assert isinstance(create_json_new, dict)
+    assert create_json_new["created"] is True
+    assert create_json_new["already_exists"] is False
+    assert isinstance(create_json_new["external_id"], str)
+    assert len(create_json_new["external_id"]) > 0
 
     default_project_name = "mode-default-project"
     default_project_path = str(
diff --git a/tests/mcp/test_tool_project_management.py b/tests/mcp/test_tool_project_management.py
index b91b3650..0856efe9 100644
--- a/tests/mcp/test_tool_project_management.py
+++ b/tests/mcp/test_tool_project_management.py
@@ -218,35 +218,6 @@ async def test_list_memory_projects_cloud_failure_graceful(app, test_project):
     assert f"- {test_project.name} (local)" in result
 
 
-@pytest.mark.asyncio
-async def test_list_memory_projects_explicit_workspace_discovery_failure_graceful(
-    app,
-    test_project,
-):
-    """Explicit workspace discovery failure still returns the local project list."""
-    with (
-        patch(
-            "basic_memory.mcp.tools.project_management.has_cloud_credentials",
-            return_value=True,
-        ),
-        patch(
-            "basic_memory.mcp.tools.project_management.resolve_workspace_parameter",
-            new_callable=AsyncMock,
-            side_effect=RuntimeError("workspace discovery unavailable"),
-        ),
-        patch(
-            "basic_memory.mcp.tools.project_management._fetch_cloud_projects",
-            new_callable=AsyncMock,
-            return_value=None,
-        ) as mock_fetch,
-    ):
-        result = await list_memory_projects(workspace="tenant-abc")
-
-    mock_fetch.assert_awaited_once_with("tenant-abc", None)
-    assert "Available projects:" in result
-    assert f"- {test_project.name} (local)" in result
-
-
 @pytest.mark.asyncio
 async def test_list_memory_projects_factory_mode(app, test_project):
     """In factory mode (cloud app), projects are reported as cloud-sourced with workspace metadata."""
@@ -345,40 +316,6 @@ async def test_list_memory_projects_factory_mode_workspace_lookup_failure(app, t
     assert "- cloud-proj (cloud)" in result
 
 
-@pytest.mark.asyncio
-async def test_list_memory_projects_factory_mode_explicit_workspace(app, test_project):
-    """In factory mode, explicit workspace param selects the matching workspace."""
-    factory_project = _make_project("cloud-proj", "/cloud-proj", is_default=True)
-    factory_list = _make_list([factory_project], default="cloud-proj")
-
-    personal_ws = _make_workspace("tenant-personal", "Personal", "personal")
-    org_ws = _make_workspace("tenant-org", "Acme Corp", "organization")
-
-    with (
-        patch(
-            "basic_memory.mcp.tools.project_management.is_factory_mode",
-            return_value=True,
-        ),
-        patch(
-            "basic_memory.mcp.clients.project.ProjectClient.list_projects",
-            new_callable=AsyncMock,
-            return_value=factory_list,
-        ),
-        patch(
-            "basic_memory.mcp.project_context.get_available_workspaces",
-            new_callable=AsyncMock,
-            return_value=[personal_ws, org_ws],
-        ),
-    ):
-        result = await list_memory_projects(output_format="json", workspace="tenant-org")
-
-    assert isinstance(result, dict)
-    proj = result["projects"][0]
-    assert proj["workspace_name"] == "Acme Corp"
-    assert proj["workspace_type"] == "organization"
-    assert proj["workspace_tenant_id"] == "tenant-org"
-
-
 @pytest.mark.asyncio
 async def test_list_memory_projects_json_with_cloud(app, test_project):
     """JSON output includes local_path, cloud_path, and source fields."""
@@ -553,32 +490,6 @@ def _make_workspace_index(workspace_projects):
     return _build_workspace_project_index(workspaces, entries)
 
 
-@pytest.mark.asyncio
-async def test_list_memory_projects_passes_explicit_workspace(app, test_project):
-    """Explicit workspace param is forwarded to _fetch_cloud_projects."""
-    cloud_list = _make_list([_make_project("cloud-proj", "/cloud-proj")])
-
-    with (
-        patch(
-            "basic_memory.mcp.tools.project_management.has_cloud_credentials",
-            return_value=True,
-        ),
-        patch(
-            "basic_memory.mcp.tools.project_management._fetch_cloud_projects",
-            new_callable=AsyncMock,
-            return_value=cloud_list,
-        ) as mock_fetch,
-        patch(
-            "basic_memory.mcp.project_context.get_available_workspaces",
-            new_callable=AsyncMock,
-            return_value=[_make_workspace("my-org-tenant-id", "My Org", "organization")],
-        ),
-    ):
-        await list_memory_projects(workspace="my-org-tenant-id")
-
-    mock_fetch.assert_awaited_once_with("my-org-tenant-id", None)
-
-
 @pytest.mark.asyncio
 async def test_list_memory_projects_aggregates_without_config_workspace(app, test_project):
     """When no explicit workspace is given, cloud discovery fans out across workspaces."""
@@ -608,84 +519,4 @@ async def test_list_memory_projects_aggregates_without_config_workspace(app, tes
         result = await list_memory_projects()
 
     mock_index.assert_awaited_once()
-    assert "- cloud-proj (cloud) [default/cloud-proj]" in result
-
-
-@pytest.mark.asyncio
-async def test_list_memory_projects_explicit_workspace_overrides_config(app, test_project):
-    """Explicit workspace takes precedence over config.default_workspace."""
-    cloud_list = _make_list([_make_project("cloud-proj", "/cloud-proj")])
-
-    with (
-        patch("basic_memory.mcp.tools.project_management.ConfigManager") as mock_cm_cls,
-        patch(
-            "basic_memory.mcp.tools.project_management.has_cloud_credentials",
-            return_value=True,
-        ),
-        patch(
-            "basic_memory.mcp.tools.project_management._fetch_cloud_projects",
-            new_callable=AsyncMock,
-            return_value=cloud_list,
-        ) as mock_fetch,
-        patch(
-            "basic_memory.mcp.project_context.get_available_workspaces",
-            new_callable=AsyncMock,
-            return_value=[_make_workspace("explicit-ws", "Explicit WS", "organization")],
-        ),
-    ):
-        mock_config = mock_cm_cls.return_value.config
-        mock_config.default_workspace = "config-default-ws"
-        await list_memory_projects(workspace="explicit-ws")
-
-    # Explicit workspace wins over config default
-    mock_fetch.assert_awaited_once_with("explicit-ws", None)
-
-
-@pytest.mark.asyncio
-async def test_list_memory_projects_json_includes_workspace_info(app, test_project):
-    """JSON output includes workspace_name, workspace_type, workspace_tenant_id for cloud projects."""
-    local_proj = _make_project("local-only", "/local/path", is_default=True)
-    local_list = _make_list([local_proj], default="local-only")
-
-    cloud_proj = _make_project("cloud-proj", "/cloud/path", id=10, external_id="cloud-uuid")
-    cloud_list = _make_list([cloud_proj])
-
-    ws = _make_workspace("org-tenant-abc", "Acme Corp", "organization")
-
-    with (
-        patch(
-            "basic_memory.mcp.clients.project.ProjectClient.list_projects",
-            new_callable=AsyncMock,
-            return_value=local_list,
-        ),
-        patch(
-            "basic_memory.mcp.tools.project_management.has_cloud_credentials",
-            return_value=True,
-        ),
-        patch(
-            "basic_memory.mcp.tools.project_management._fetch_cloud_projects",
-            new_callable=AsyncMock,
-            return_value=cloud_list,
-        ),
-        patch(
-            "basic_memory.mcp.project_context.get_available_workspaces",
-            new_callable=AsyncMock,
-            return_value=[ws],
-        ),
-    ):
-        result = await list_memory_projects(output_format="json", workspace="org-tenant-abc")
-
-    assert isinstance(result, dict)
-    by_name = {p["name"]: p for p in result["projects"]}
-
-    # Cloud project carries workspace info
-    cloud = by_name["cloud-proj"]
-    assert cloud["workspace_name"] == "Acme Corp"
-    assert cloud["workspace_type"] == "organization"
-    assert cloud["workspace_tenant_id"] == "org-tenant-abc"
-
-    # Local-only project has no workspace info
-    local = by_name["local-only"]
-    assert local["workspace_name"] is None
-    assert local["workspace_type"] is None
-    assert local["workspace_tenant_id"] is None
+    assert "- cloud-proj (cloud) [00000000-0000-0000-0000-000000000001]" in result
diff --git a/tests/mcp/test_tool_telemetry.py b/tests/mcp/test_tool_telemetry.py
index a689bfdb..64550f71 100644
--- a/tests/mcp/test_tool_telemetry.py
+++ b/tests/mcp/test_tool_telemetry.py
@@ -63,7 +63,7 @@ async def test_write_note_emits_root_operation_and_project_context(
             "entrypoint": "mcp",
             "tool_name": "write_note",
             "requested_project": test_project.name,
-            "workspace_id": None,
+            "requested_project_id": None,
             "note_type": "note",
             "overwrite": False,
             "output_format": "json",
@@ -108,7 +108,7 @@ async def test_read_note_emits_root_operation_and_project_context(
             "entrypoint": "mcp",
             "tool_name": "read_note",
             "requested_project": test_project.name,
-            "workspace_id": None,
+            "requested_project_id": None,
             "output_format": "json",
             "include_frontmatter": True,
         },
@@ -156,7 +156,7 @@ async def test_search_notes_emits_root_operation_and_project_context(
             "entrypoint": "mcp",
             "tool_name": "search_notes",
             "requested_project": test_project.name,
-            "workspace_id": None,
+            "requested_project_id": None,
             "search_type": "text",
             "output_format": "json",
             "page": 1,
@@ -209,7 +209,7 @@ async def test_edit_note_emits_root_operation_and_project_context(
             "entrypoint": "mcp",
             "tool_name": "edit_note",
             "requested_project": test_project.name,
-            "workspace_id": None,
+            "requested_project_id": None,
             "edit_operation": "append",
             "output_format": "json",
             "has_section": False,
@@ -261,7 +261,7 @@ async def test_build_context_emits_root_operation_and_project_context(
             "entrypoint": "mcp",
             "tool_name": "build_context",
             "requested_project": test_project.name,
-            "workspace_id": None,
+            "requested_project_id": None,
             "depth": 2,
             "timeframe": "7d",
             "page": 1,
diff --git a/tests/services/test_search_service.py b/tests/services/test_search_service.py
index 609c68ae..bc88bdc7 100644
--- a/tests/services/test_search_service.py
+++ b/tests/services/test_search_service.py
@@ -259,9 +259,7 @@ async def test_delete_entity_without_permalink(search_service, sample_entity):
 
 
 @pytest.mark.asyncio
-async def test_handle_delete_clears_entity_vectors(
-    search_service, sample_entity, monkeypatch
-):
+async def test_handle_delete_clears_entity_vectors(search_service, sample_entity, monkeypatch):
     """Regression guard for #764: handle_delete must drive vector-row cleanup
     so deleting an entity doesn't leave orphaned rows in `search_vector_chunks`
     or `search_vector_embeddings`.
@@ -288,8 +286,7 @@ async def spy_delete_entity_vector_rows(entity_id: int) -> None:
     await search_service.handle_delete(sample_entity)
 
     assert calls == [sample_entity.id], (
-        f"handle_delete must call delete_entity_vector_rows({sample_entity.id}); "
-        f"got calls={calls}"
+        f"handle_delete must call delete_entity_vector_rows({sample_entity.id}); got calls={calls}"
     )