{
  "description": "Session logs demonstrating issue #1540 - OpenAI reasoning block causes 400 error",
  "context": {
    "session_type": "Discord channel",
    "initial_model": "anthropic/claude-sonnet-4-5",
    "switched_to": "openai/gpt-5.2-codex",
    "clawdbot_version": "2026.1.16-2"
  },
  "sequence": [
    {
      "step": 1,
      "description": "User switches model mid-session from Anthropic to OpenAI",
      "command": "/model gpt-5.2-codex"
    },
    {
      "step": 2,
      "description": "First GPT-5.2-codex response generates thinkingSignature with OpenAI reasoning format",
      "log": {
        "type": "message",
        "timestamp": "2026-01-23T20:32:52.772Z",
        "message": {
          "role": "assistant",
          "content": [
            {
              "type": "thinking",
              "thinking": "**Reading playbook contents**\n\nI am preparing to read the playbook file to retrieve and display its contents as requested.",
              "thinkingSignature": {
                "id": "rs_07274b660fef5363006973daf27e348190bc09ed53bcc7fa0b",
                "type": "reasoning",
                "encrypted_content": "[REDACTED - base64 encrypted reasoning content]",
                "summary": [
                  {
                    "type": "summary_text",
                    "text": "**Reading playbook contents**..."
                  }
                ]
              }
            }
          ],
          "api": "openai-responses",
          "provider": "openai",
          "model": "gpt-5.2-codex",
          "stopReason": "toolUse"
        }
      }
    },
    {
      "step": 3,
      "description": "All subsequent requests fail with 400 error - orphaned reasoning item",
      "logs": [
        {
          "timestamp": "2026-01-23T20:35:36.968Z",
          "message": {
            "role": "assistant",
            "api": "openai-responses",
            "provider": "openai",
            "model": "gpt-5.2-codex",
            "stopReason": "error",
            "errorMessage": "400 Item 'rs_07274b660fef5363006973daf27e348190bc09ed53bcc7fa0b' of type 'reasoning' was provided without its required following item."
          }
        },
        {
          "timestamp": "2026-01-23T20:35:58.979Z",
          "message": {
            "role": "assistant",
            "api": "openai-responses",
            "provider": "openai",
            "model": "gpt-5.2-codex",
            "stopReason": "error",
            "errorMessage": "400 Item 'rs_07274b660fef5363006973daf27e348190bc09ed53bcc7fa0b' of type 'reasoning' was provided without its required following item."
          }
        },
        {
          "timestamp": "2026-01-23T20:39:49.894Z",
          "message": {
            "role": "assistant",
            "api": "openai-responses",
            "provider": "openai",
            "model": "gpt-5.2-codex",
            "stopReason": "error",
            "errorMessage": "400 Item 'rs_07274b660fef5363006973daf27e348190bc09ed53bcc7fa0b' of type 'reasoning' was provided without its required following item."
          }
        }
      ]
    }
  ],
  "root_cause": "The thinkingSignature contains an OpenAI reasoning block ID (rs_...) that gets replayed to the API. OpenAI Responses API requires reasoning blocks to be followed by their corresponding content item. When the history is re-submitted, the orphaned reasoning ID causes a 400 error.",
  "workaround_applied": "Manually edited transcript to remove thinkingSignature fields and error messages"
}