fix(providers): normalize tool schemas for JSON Schema 2020-12 compliance (Bedrock/LiteLLM)

[umi008]

Related GitHub Issue

Closes: #869

Description

Tool requests through the OpenAI Compatible provider path (used by 15+ providers including LiteLLM, OpenRouter, DeepSeek, xAI, etc.) were sending raw tool schemas without JSON Schema 2020-12 normalization. When the backend is AWS Bedrock (directly or through a LiteLLM proxy), it rejects schemas containing keywords like maxItems on array properties because Bedrock enforces strict 2020-12 compliance.

normalizeToolSchema() was already applied in the direct Bedrock and VSCode LM provider paths, but BaseProvider.convertToolSchemaForOpenAI() — the shared method used by all OpenAI-compatible providers — was not calling it.

Fix: convertToolSchemaForOpenAI() now calls normalizeToolSchema() first to convert deprecated type arrays to anyOf, strip unsupported format values, and enforce additionalProperties: false, before applying OpenAI-specific strict mode transforms (all-required, null removal). The two passes compose safely: normalization handles 2020-12 compliance, and the existing OpenAI pass adds the strict-mode constraints on top.

Test Procedure

1. Configure an OpenAI Compatible provider pointing at a LiteLLM proxy backed by AWS Bedrock (or any backend enforcing strict JSON Schema 2020-12)
2. Send a tool-enabled request (Code/Architect/Orchestrator mode)
3. Verify the request succeeds — no 400 error about unsupported keywords like maxItems

Manual verification of schema transformation:

// Before: type arrays and maxItems pass through unchecked
// After: normalizeToolSchema() converts type arrays → anyOf and strips unsupported keywords

Pre-Submission Checklist

• Issue Linked: Closes [BUG] OpenAI Compatible provider (Bedrock backend) rejects maxItems in tool schema — normalizeToolSchema() fix may not cover this code path #869
• Scope: One focused fix — normalizes schemas at the shared provider layer
• Self-Review: Verified the two normalization passes compose correctly; TypeScript compiles clean
• Testing: Existing provider tests cover the transform path; TypeScript compilation verified
• Documentation Impact: No documentation updates required
• Contribution Guidelines: Read and agree

Screenshots / Videos

N/A — backend schema normalization, no UI changes.

Documentation Updates

• No documentation updates are required.

Additional Notes

This fix benefits all providers that inherit from BaseProvider and use convertToolsForOpenAI() — OpenRouter, DeepSeek, xAI, Groq, Fireworks, Together, SambaNova, Baseten, Friendli, and others. The normalization is idempotent for well-formed schemas, so the risk of regression is minimal.

Summary by CodeRabbit

• Bug Fixes
  • Improved compatibility when converting tool schemas for OpenAI.
  • Added safer handling for invalid or unexpected schema formats.
  • Normalizes incoming JSON schemas before applying OpenAI strict-mode transformations to improve consistency and reliability.

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Review details

⚙️ Run configuration

Configuration used: defaults

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📥 Commits

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📒 Files selected for processing (1)

• src/api/providers/__tests__/base-provider.spec.ts

📝 Walkthrough

Walkthrough

BaseProvider now normalizes tool schemas for JSON Schema 2020-12 compliance before applying OpenAI strict-mode transformations, with guards for invalid inputs and normalized results.

Changes

OpenAI tool schema normalization

Layer / File(s)	Summary
Normalize schemas before OpenAI conversion src/api/providers/base-provider.ts	convertToolSchemaForOpenAI validates the input, calls normalizeToolSchema, validates the normalized object schema, and builds the conversion result from the normalized copy. Documentation and imports reflect the new normalization step.

Estimated code review effort: 2 (Simple) | ~10 minutes

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Linked Issues check	✅ Passed	The change matches issue #869 by normalizing shared OpenAI-compatible tool schemas before Bedrock-strict transforms.
Out of Scope Changes check	✅ Passed	The diff stays focused on the schema-normalization fix in BaseProvider and shows no unrelated changes.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.
Title check	✅ Passed	The title clearly summarizes the main change: normalizing tool schemas for OpenAI-compatible providers.
Description check	✅ Passed	The description follows the template well, includes the linked issue, implementation summary, testing steps, and checklist items.

✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests

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Actionable comments posted: 1

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Verify each finding against current code. Fix only still-valid issues, skip the
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Inline comments:
In `@src/api/providers/base-provider.ts`:
- Around line 70-84: Update the schema handling around normalizeToolSchema so
object-like normalized schemas with properties and additionalProperties: false
are processed even when type is absent, rather than returning early; use an
object-shape check that also covers flattened compositions and nullable object
conversions. In the same logic, remove the redundant Array.isArray(prop.type)
branch and rely on normalizeToolSchema’s recursive type-array normalization
before applying strict required-field and nested-property processing.

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Fix all unresolved CodeRabbit comments on this PR:

• Push a commit to this branch (recommended)
• Create a new PR with the fixes

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ℹ️ Review info

⚙️ Run configuration

Configuration used: defaults

Review profile: CHILL

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Run ID: 8f75b99a-dfae-41c8-8a20-c5926d1ab896

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Reviewing files that changed from the base of the PR and between 116b70e and 351d15e.

📒 Files selected for processing (1)

• src/api/providers/base-provider.ts

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✅ All modified and coverable lines are covered by tests.

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