500 error when configuring Mistral AI API key

[bekossy]

Configuring the Mistral AI provider fails with a backend 500 error and the API key cannot be saved.

Steps to reproduce:

• Go to Settings
• Open Models
• Click Configure now for Mistral AI
• Enter API key
• Click Confirm

Request payload:

{
  "header": {
    "name": "Mistral AI",
    "description": ""
  },
  "secret": {
    "kind": "provider_key",
    "data": {
      "provider": {
        "key": "TEST_KEY"
      }
    }
  }
}

[linear]

AGE-3695

[dosubot]

This looks like a potential backend validation or configuration issue. A few things to check:

Most likely cause: There may be a payload structure mismatch between what the frontend sends and what the backend expects. The validator logic expects a nested structure (data["provider"]["key"]), but test fixtures show a flat structure like {"provider": "openai", "key": "sk-xxx"}.

Other potential causes:

• Missing encryption key: The PGPString field will throw an error if AGENTA_CRYPT_KEY isn't properly configured
• Provider identifier: The Mistral provider identifier was changed from "mistralai" to "mistral" - worth confirming the correct value is being used

To investigate further: Check the backend logs for the specific error details - all exceptions are logged with a support_id that would help pinpoint the exact failure.

There's also a related UI bug (AGE-3443) where provider configurations incorrectly default to Mistral AI.

To reply, just mention @dosu.

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