docs/bugs/INVESTIGATION_INVALID_MODELS.md

Bug Investigation: Invalid Default LLM Models

Status

• Date: 2025-11-29
• Reporter: CLI User
• Component: src/utils/config.py
• Priority: High (Magentic Mode Blocker)
• Resolution: FIXED

Issue Description

The user encountered a 403 error when running in Magentic mode: Error code: 403 - {'error': {'message': 'Project ... does not have access to model gpt-5.1', ... 'code': 'model_not_found'}}

This indicates the application is trying to use gpt-5.1, which the user's API key did not have access to (likely a beta/gated model).

Root Cause Analysis

The default config used gpt-5.1 (beta/preview) and claude-sonnet-4-5-20250929. Initial remediation mistakenly downgraded these to 2024 models (gpt-4o). Web search confirmed that in November 2025:

• claude-sonnet-4-5-20250929 IS valid.
• gpt-5.1 exists but access is restricted (leading to 403).
• gpt-5 (August 2025) is the stable flagship.

Solution Implemented

Updated src/utils/config.py to use:

• anthropic_model: claude-sonnet-4-5-20250929 (Restored correct Nov 2025 model)
• openai_model: gpt-5 (Changed from 5.1 to 5 to ensure stability/access).

Verification

• tests/unit/agent_factory/test_judges_factory.py updated and passed.