[waleedlatif1]

Summary

• json and any tool params are no longer advertised as type: "object". About 994 params were affected, many of them arrays: cbinsights_list_business_relationships.orgIds is described as "e.g. [129410, 1034157]" yet typed as an object. The model saw a contradiction, and validators that honor the type rejected correct calls (Pi local dev's pi-ai did). These params now carry no type, which allows any JSON value; the description stays.
• MCP argument errors now name what is wrong, e.g. "Invalid MCP operation arguments: must have required property 'query'; /limit must be integer" (up to 3 Ajv errors, extra keys named), instead of only "Invalid MCP operation arguments". Agents can now repair a call instead of retrying blind.
• McpClient.getNegotiatedVersion() returns the transport's negotiated protocol version. It returned the server's Implementation object, so logs and the test-connection response always showed undefined.

Type of Change

• Bug fix

Testing

• params.test.ts: a json/any param accepts both an array and an object under Ajv, for both the LLM and copilot schema surfaces. The legacy snapshot expectation changes deliberately.
• execute-tool.test.ts: names each invalid argument (fails before the fix), and accepts valid arguments.
• Every consumer of buildParameterSchema was checked: OpenAI tools are sent non-strict, Anthropic, Bedrock and Gemini pass untyped properties through (MCP tools already do), and the worker treats input_schema as opaque.
• The 6 touched test files (89 tests) pass, and bun run type-check passes. CI runs the rest.

Checklist

• Code follows project style guidelines
• Self-reviewed my changes
• Tests added/updated and passing
• No new warnings introduced
• I confirm that I have read and agree to the terms outlined in the Contributor License Agreement (CLA)

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1 Skipped Deployment

Project	Deployment	Actions	Updated
docs	Skipped		Oct 21, 2026 12:01am UTC

[greptile-apps]

Confidence Score: 5/5

[Medium impact] The PR appears safe to merge; no actionable issues were found.

Summary

The PR lets json and any tool parameters accept any JSON value and makes MCP argument errors more useful.

• json and any tool values can be arrays or objects.
• MCP argument errors name the first problem in a tool call.
• MCP connection details show the protocol version the server agreed to.

Changes since the previous review stop collecting every validation error and update the tests to expect one named failure. No new actionable issues were found.

_{Reviews (2) · Last reviewed commit: "fix(mcp): report the first invalid argum..." · Reviewed by Greptile}

[cubic-dev-ai]

All reported issues were addressed across 6 files

<sub>Reply with feedback, questions, or to request a fix.

Turn on auto-fix | Re-trigger cubic</sub>

[waleedlatif1]

@greptile

[waleedlatif1]

@cubic-dev-ai review this PR

[cubic-dev-ai]

@cubic-dev-ai review this PR

@waleedlatif1 I have started the AI code review. It will take a few minutes to complete.

[cubic-dev-ai]

No issues found across 6 files

Confidence score: 5/5

• Automated review surfaced no issues in the provided summaries.
• No files require special attention.

_{Turn on auto-fix | Re-trigger cubic}