fix: lazy provider creation for goose acp (#7026)

[codefromthecrypt]

Summary

Before, goose acp crashes on startup when there is not yet Goose configuration.

This PR makes provider creation lazy until an ACP session needs it.

This also adds missing ACP authMethods is added to the initialize response so ACP clients can prompt for setup.

Type of Change

• Bug fix

AI Assistance

• This PR was created or reviewed with AI assistance

Testing

• New test_initialize_without_provider test verifies configuration isn't required to initialize ACP.

• ACP registry validation against local build:

cargo build --release -p goose-cli

# Check out the registry PR that adds goose
cd ../registry
gh pr checkout 23
rm -rf .sandbox /tmp/empty-goose-home && mkdir -p /tmp/empty-goose-home

# Place binary and dummy archive so the verifier skips the download
mkdir -p .sandbox/binary/goose/extracted
cp ../goose-2/target/release/goose .sandbox/binary/goose/extracted/goose
touch .sandbox/binary/goose/goose-aarch64-apple-darwin.tar.bz2

# Run the same auth check the registry CI runs, pointing to an empty directory
GOOSE_PATH_ROOT=/tmp/empty-goose-home uv run --python 3.12 .github/workflows/verify_agents.py --agent goose --auth-check

Example output:

$ ± |add-goose-agent ✓| → GOOSE_PATH_ROOT=/tmp/empty-goose-home uv run --python 3.12 .github/workflows/verify_agents.py --agent goose --auth-check                     
Platform: darwin-aarch64
Registry: /Users/codefromthecrypt/oss/registry
Sandbox:  /Users/codefromthecrypt/oss/registry/.sandbox

Found 10 agents

Verifying 1 agent(s): goose

[1/1] goose (binary)
  Testing binary...
    → Auth check: /Users/codefromthecrypt/oss/registry/.sandbox/binary/goose/extracted/goose acp...
    ✓ Success: Auth OK: goose-provider(agent)
    Sandbox: /Users/codefromthecrypt/oss/registry/.sandbox/binary/goose

==================================================
Summary
==================================================
  Passed:  1
  Failed:  0
  Skipped: 0

All tests passed!

Sandboxes available at: /Users/codefromthecrypt/oss/registry/.sandbox

Related Issues

Fixes #7026
Unblocks agentclientprotocol/registry#23

[Copilot]

Pull request overview

Fixes ACP startup behavior by moving provider instantiation behind a lazy ProviderConstructor, and updates ACP initialization to advertise supported auth methods so registry validation can succeed.

Changes:

• Make provider creation lazy by passing a ProviderConstructor into GooseAcpAgent and only constructing a provider when a session needs it.
• Add authMethods to the ACP initialize response.
• Update goose-acp test fixtures and add a new test covering initialize without an available provider.

Reviewed changes

Copilot reviewed 6 out of 6 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
crates/goose/src/providers/provider_registry.rs	Exposes ProviderConstructor publicly for cross-crate use.
crates/goose-acp/src/server.rs	Refactors agent construction to accept a provider factory; adds authMethods; introduces lazy provider setup via ensure_provider.
crates/goose-acp/src/server_factory.rs	Updates HTTP/WS server factory to build GooseAcpAgent using ProviderConstructor.
crates/goose-acp/tests/fixtures/mod.rs	Refactors in-process test server wiring to return a ready-to-use transport and adds initialize_agent helper.
crates/goose-acp/tests/fixtures/server.rs	Adapts tests to the updated in-process server spawn API.
crates/goose-acp/tests/server_test.rs	Adds test_initialize_without_provider and updates imports for new helpers/types.

[Copilot]

Pull request overview

Copilot reviewed 7 out of 8 changed files in this pull request and generated 3 comments.