Add OpenAI function calling support

[jorge123255]

Major feature addition implementing full OpenAI function calling compatibility:

• Complete support for OpenAI's tools and tool_choice parameters
• Legacy functions/function_call format support
• All 9 Claude tools accessible via OpenAI API format
• GET /v1/tools endpoint to list available tools
• Comprehensive tool mapping and execution handling
• Full Swagger/OpenAPI documentation updates
• Extensive test suite and examples

[RichardAtCT]

@claude

[claude]

Claude encountered an error —— View job

Failed with exit code 128

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I'll analyze this and get back to you.

[RichardAtCT]

Review of PR #7: OpenAI Function Calling Support

Thank you for this comprehensive PR! The effort to implement OpenAI function calling is appreciated. However, after thorough testing and review, I've identified several fundamental issues that need to be addressed.

🔍 Testing Results

I tested the implementation with both the provided examples and custom tests:

• ✅ /v1/tools endpoint works correctly, returning all 9 tools
• ✅ enable_tools flag works (existing functionality)
• ❌ OpenAI function calling format doesn't produce structured tool calls
• ❌ Tools are executed but results aren't returned in OpenAI format

🚨 Major Issues

1. Fundamental Architecture Mismatch

   • OpenAI expects: Assistant returns tool_calls → User executes → User sends results → Assistant responds
   • Claude Code: Executes tools directly during generation and returns results inline
   • The PR doesn't bridge this execution model difference

2. Tool Name Mapping Errors

   • PR uses lowercase: "read", "write", "bash"
   • Claude Code expects: "Read", "Write", "Bash"
   • This causes tool configuration to fail

3. Incomplete Tool Response Parsing

   • extract_tool_calls_from_message only detects bash blocks and file reads
   • Doesn't parse Claude's actual tool usage format
   • No mechanism to convert inline results to structured tool_calls

4. Missing Functionality

   • tool_choice parameter accepted but ignored
   • Legacy functions/function_call format incomplete
   • No proper error handling for tool execution failures

💡 Recommendations

This PR needs significant rework. Consider these approaches:

Option 1: Full Implementation

• Intercept Claude's response before tool execution
• Parse tool intents and return structured tool_calls
• Allow client to execute tools and send results back
• This requires deep integration with Claude Code SDK

Option 2: Documentation Approach

• Clearly document that OpenAI function calling isn't supported
• Explain the architectural differences
• Keep enable_tools as the recommended approach
• Provide migration guide for OpenAI users

Option 3: Hybrid Approach

• Support tool definitions for documentation/discovery
• Execute tools server-side (current behavior)
• Return execution summary in a structured format
• Document the differences from OpenAI's model

✅ Positive Aspects

• Clean code structure and organization
• Comprehensive documentation updates
• Good OpenAPI schema additions
• Thoughtful tool registry implementation

📋 Required Changes

Before this can be merged:

1. Fix tool name mappings (capitalize tool names)
2. Implement proper tool usage detection
3. Add tests that verify actual function calling behavior
4. Either implement proper OpenAI compatibility or document limitations
5. Handle edge cases (tool failures, multiple tool calls, etc.)

🤔 Question

What's the primary use case for this feature? Understanding the specific needs would help determine the best approach. If it's for OpenAI SDK compatibility, we might need to reconsider the implementation strategy given the fundamental differences in how tools work.

Thank you again for your contribution! I'm happy to discuss potential solutions or help with the implementation.