No reasoning at all through Github Copilot provider

[Coruscant11]

Description

Validate thinking in VSCode

Attempt to get thinking in opencode

opencode.jsonc

{
  "$schema": "https://opencode.ai/config.json",
  "theme": "aura",
  "autoupdate": true,
  "provider": {
    "github-copilot": {
      "models": {
        "[Custom] Opus 4.5 Thinking": {
          "id": "claude-opus-4.5",
          "reasoning": true,
          "options": {
            "thinking": {
              "type": "enabled",
              "budgetTokens": 32000,
            },
          }
        },
      }
    }
  }
}

A conversation example:

opencode export

{
  "info": {
    "id": "ses_4753afc9affenaSxWVHstiDVAN",
    "version": "1.1.1",
    "projectID": "e53faf218247b17967230b742668df6addde9727",
    "directory": "/home/jcarlens/Development/sesm",
    "title": "Checking assistant reasoning",
    "time": {
      "created": 1767559725925,
      "updated": 1767559730475
    },
    "summary": {
      "additions": 0,
      "deletions": 0,
      "files": 0
    }
  },
  "messages": [
    {
      "info": {
        "id": "msg_b8ac50368001zOrnH6Xk5rnVK3",
        "sessionID": "ses_4753afc9affenaSxWVHstiDVAN",
        "role": "user",
        "time": {
          "created": 1767559725933
        },
        "summary": {
          "title": "Asking about reasoning",
          "diffs": []
        },
        "agent": "build",
        "model": {
          "providerID": "github-copilot",
          "modelID": "[Custom] Opus 4.5 Thinking"
        }
      },
      "parts": [
        {
          "id": "prt_b8ac50368002yxYgBf1OX3yO1R",
          "sessionID": "ses_4753afc9affenaSxWVHstiDVAN",
          "messageID": "msg_b8ac50368001zOrnH6Xk5rnVK3",
          "type": "text",
          "text": "Are you reasoning?"
        }
      ]
    },
    {
      "info": {
        "id": "msg_b8ac503730018iRxad0NY14TX9",
        "sessionID": "ses_4753afc9affenaSxWVHstiDVAN",
        "role": "assistant",
        "time": {
          "created": 1767559725939,
          "completed": 1767559730467
        },
        "parentID": "msg_b8ac50368001zOrnH6Xk5rnVK3",
        "modelID": "[Custom] Opus 4.5 Thinking",
        "providerID": "github-copilot",
        "mode": "build",
        "agent": "build",
        "path": {
          "cwd": "/home/jcarlens/Development/sesm",
          "root": "/home/jcarlens/Development/sesm"
        },
        "cost": 0,
        "tokens": {
          "input": 327,
          "output": 77,
          "reasoning": 0,
          "cache": {
            "read": 10534,
            "write": 0
          }
        },
        "finish": "stop"
      },
      "parts": [
        {
          "id": "prt_b8ac5101b001lc4JrFFJfRMDvj",
          "sessionID": "ses_4753afc9affenaSxWVHstiDVAN",
          "messageID": "msg_b8ac503730018iRxad0NY14TX9",
          "type": "step-start",
          "snapshot": "e0066eb511d26f679f2ba4739f14047f10f435aa"
        },
        {
          "id": "prt_b8ac5101c001ZUyiAP75JVK2pe",
          "sessionID": "ses_4753afc9affenaSxWVHstiDVAN",
          "messageID": "msg_b8ac503730018iRxad0NY14TX9",
          "type": "text",
          "text": "No, I'm not using an extended reasoning or \"thinking\" mode. I'm a standard Claude model responding directly to your messages. I process your input and generate responses, but I don't have a separate visible chain-of-thought or reasoning trace that I'm working through before answering.\n\nIs there something specific you'd like help with in your project?",
          "time": {
            "start": 1767559730442,
            "end": 1767559730442
          }
        },
        {
          "id": "prt_b8ac5150c001FbC86cMHHQDIoA",
          "sessionID": "ses_4753afc9affenaSxWVHstiDVAN",
          "messageID": "msg_b8ac503730018iRxad0NY14TX9",
          "type": "step-finish",
          "reason": "stop",
          "snapshot": "e0066eb511d26f679f2ba4739f14047f10f435aa",
          "cost": 0,
          "tokens": {
            "input": 327,
            "output": 77,
            "reasoning": 0,
            "cache": {
              "read": 10534,
              "write": 0
            }
          }
        }
      ]
    }
  ]
}

I also tried to put any value in the reasoning, nothing seems to break the API. Maybe the options are ignored?

Thanks for your hardwork!

Plugins

No response

OpenCode version

1.1.1

Steps to reproduce

1. Connect to github copilot provider
2. Either use built-in Opus 4.5 with any built-in variants, or try to configure a custom model
3. Ask anything to see a chain of thougth

Screenshot and/or share link

No response

Operating System

Ubuntu 24.04

Terminal

Ghostty