GitHub Copilot GPT-6 models do not send selected reasoning effort #51850

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1. github-actions

   assigned

   kitlangton

   on Sep 28, 2026
2. github-actions commented on Sep 28, 2026

   

   github-actionsBot

   on Sep 28, 2026 – with GitHub Actions

   Contributor

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   This issue might be a duplicate of existing issues. Please check:

   • #48247: GPT-6 model-ID handling in provider request transforms affects reasoning-related options. That issue focuses on Azure behavior, so please check whether its investigation also covers the missing reasoning effort on GitHub Copilot.
3. andrii-riabchun commented on Sep 28, 2026

   

   andrii-riabchun

   on Sep 28, 2026

   Author

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   Made a plugin to workaround the issue

   // ~/.config/opencode/plugins/github-copilot-gpt6-reasoning.ts
   
   const COPILOT_HOST = "api.githubcopilot.com"
   const COPILOT_RESPONSES_PATH = /(?:^|\/)responses(?:\/|$)/
   
   function isCopilotResponsesRequest(url: string) {
     try {
       const parsed = new URL(url)
       return parsed.hostname === COPILOT_HOST && COPILOT_RESPONSES_PATH.test(parsed.pathname)
     } catch {
       return false
     }
   }
   
   export default {
     id: "github-copilot.gpt6-reasoning",
   
     async setup(ctx: any) {
       await ctx.session.hook("http.request", async (event: any) => {
         if (!isCopilotResponsesRequest(event.request.url)) return
   
         try {
           // Copilot Responses bodies look like {"model":"gpt-6","input":[...]}; `include` and `reasoning` may be absent.
           // Clone the one-shot body before parsing, and replace the request only after the rewrite succeeds.
           const body = JSON.parse(await event.request.clone().text()) as Record<string, unknown>
           const model = event.model
           const effort = model?.variant
   
           if (
             model?.providerID === "github-copilot" &&
             typeof model.id === "string" &&
             model.id.startsWith("gpt-6") &&
             typeof effort === "string" &&
             typeof body.model === "string" &&
             body.model.startsWith("gpt-6")
           ) {
             // GitHub Copilot's GPT-6 Responses route needs reasoning in the raw body; OpenCode's option is not forwarded.
             body.reasoning = { effort, summary: "auto" }
             const include = Array.isArray(body.include) ? body.include : []
   
             if (!include.includes("reasoning.encrypted_content")) {
               include.push("reasoning.encrypted_content")
             }
   
             body.include = include
             event.request = new Request(event.request, { body: JSON.stringify(body) })
           }
         } catch {
           // Leave malformed requests untouched.
         }
       })
     },
   }
4. rekram1-node commented on Sep 29, 2026

   

   rekram1-node

   on Sep 29, 2026

   Collaborator

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   Some of our copilot support has been slacking, ill polish it soon

   ❤️React with ❤️1Reacted by Andrii Riabchun
5. rekram1-node

   closed this as completedon Sep 29, 2026
6. rekram1-node commented on Sep 29, 2026

   

   rekram1-node

   on Sep 29, 2026

   Collaborator

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   Merged fix, will release later