properly convert custom / mcp tools to anthropic cua format

[tkattkat]

Why

Custom AI SDK tools and MCP integrations weren't working properly with Anthropic CUA - parameters were empty {} and tools weren't tracked.

What Changed

• Convert Zod schemas to JSON Schema before sending to Anthropic (using zodToJsonSchema)
• Track custom tool calls in the actions array
• Silence "Unknown tool name" warnings for custom tools

Test Plan

Tested with examples file.

Parameters passed correctly ({"city":"San Francisco"} instead of {})
Custom tools execute and appear in actions array
No warnings

[changeset-bot]

🦋 Changeset detected

Latest commit: ac46fb6

The changes in this PR will be included in the next version bump.

Not sure what this means? Click here to learn what changesets are.

Click here if you're a maintainer who wants to add another changeset to this PR

[greptile-apps]

Greptile Overview

Summary

This PR fixes a critical integration issue with custom AI SDK tools and MCP (Model Context Protocol) integrations when using Anthropic's Computer Use API (CUA). The core problem was that Zod schemas used by AI SDK tools weren't being properly converted to the JSON Schema format expected by Anthropic's API, resulting in empty parameters `{}` being passed to tools instead of the actual parameter values.

The changes enhance the AnthropicCUAClient class in three key ways:

1. Schema Conversion: Imports and uses zodToJsonSchema to properly convert Zod schemas to JSON Schema format before sending tool definitions to the Anthropic API. This ensures that tool parameters are correctly structured and populated.

2. Action Tracking: Adds tracking for custom tool executions in the actions array by creating custom_tool action entries when custom tools are invoked. This improves observability and debugging capabilities.

3. Warning Suppression: Silences "Unknown tool name" warnings for registered custom tools, cleaning up the logging output and reducing noise for legitimate tool usage.

These changes integrate seamlessly with the existing agent architecture, building on the AnthropicCUAClient's existing tool handling infrastructure while fixing the schema conversion gap that prevented proper parameter passing to custom tools.

Important Files Changed

Changed Files

Filename	Score	Overview
lib/agent/AnthropicCUAClient.ts	4/5	Fixes custom tool integration by adding Zod to JSON Schema conversion, custom tool action tracking, and warning suppression

Confidence score: 4/5

• This PR addresses a specific integration bug with clear, targeted fixes that are unlikely to cause regressions
• Score reflects well-contained changes that solve a legitimate problem without introducing complex new logic paths
• Pay close attention to the schema conversion logic to ensure zodToJsonSchema handles all edge cases properly

Sequence Diagram

sequenceDiagram
    participant User
    participant AnthropicCUAClient
    participant AnthropicAPI as "Anthropic API"
    participant CustomTool as "Custom/MCP Tool"
    participant Logger

    User->>AnthropicCUAClient: "execute(instruction, tools)"
    AnthropicCUAClient->>Logger: "log: Starting execution"
    
    loop For each step (until completion or maxSteps)
        AnthropicCUAClient->>AnthropicCUAClient: "createInitialInputItems(instruction)"
        AnthropicCUAClient->>AnthropicCUAClient: "convertCustomToolsToJsonSchema()"
        Note over AnthropicCUAClient: Uses zodToJsonSchema to convert Zod schemas
        
        AnthropicCUAClient->>AnthropicAPI: "messages.create(with custom tools)"
        AnthropicAPI-->>AnthropicCUAClient: "response with tool_use blocks"
        
        AnthropicCUAClient->>Logger: "log: Processing content blocks"
        
        loop For each tool_use block
            alt Computer tool
                AnthropicCUAClient->>AnthropicCUAClient: "convertToolUseToAction()"
                AnthropicCUAClient->>AnthropicCUAClient: "captureScreenshot()"
            else Custom tool
                AnthropicCUAClient->>CustomTool: "execute(input)"
                CustomTool-->>AnthropicCUAClient: "tool result"
                AnthropicCUAClient->>AnthropicCUAClient: "create custom_tool action"
                Note over AnthropicCUAClient: Now tracks custom tools in actions array
            end
            
            AnthropicCUAClient->>Logger: "log: Tool execution result"
        end
        
        AnthropicCUAClient->>AnthropicCUAClient: "takeAction(toolUseItems)"
        AnthropicCUAClient->>AnthropicCUAClient: "updateInputItemsForNextStep()"
    end
    
    AnthropicCUAClient-->>User: "AgentResult with actions and usage"

Loading

_{1 file reviewed, 1 comment}

_{Edit Code Review Agent Settings | Greptile}