Hosted MCP cannot resolve review threads with a fine-grained PAT that succeeds via GraphQL

Comienza en el punto de entrada de la herramienta alojada de MCP para resolver hilos de revisión y reproduce el fallo utilizando el endpoint, los toolsets y el fine-grained PAT indicados. Compara la ruta de autorización de la operación con la mutación GraphQL resolveReviewThread exitosa. La tarea está completada cuando la operación de MCP resuelva el hilo de revisión con el mismo token y conserve el comportamiento existente de inline-reply.

Summary

GitHub hosted remote MCP fails to resolve pull request review threads with a fine-grained personal access token, returning:

Resource not accessible by personal access token

The same token successfully performs both unresolveReviewThread and resolveReviewThread through GitHub GraphQL. This appears related to #2381, which reports a different hosted-MCP PR operation failing while the equivalent direct API request succeeds.

Environment

• Server: GitHub-hosted remote MCP
• Endpoint: https://api.githubcopilot.com/mcp/
• Transport: Remote HTTP
• Client: OpenCode
• Authentication: fine-grained PAT supplied in the Authorization: Bearer header
• MCP toolsets: repos,issues,pull_requests
• Repository: crsiebler/pogo-gbl-analyzer
• Token repository permission: Pull requests: Read and write
• Approximate failure time: 2026-09-08 05:35 UTC

Reproduction

1. Configure the hosted server with oauth: false, the endpoint above, an Authorization: Bearer {env:GITHUB_MCP_TOKEN} header, and X-MCP-Toolsets: repos,issues,pull_requests.
2. Authenticate with a fine-grained PAT that has access to crsiebler/pogo-gbl-analyzer and Pull requests: Read and write.
3. Read review threads for crsiebler/pogo-gbl-analyzer#10.
4. Attempt to resolve PRRT_kwDOPgvNY86gGnRD with the MCP review-thread resolution tool.
5. Observe:

failed to resolve review thread: Resource not accessible by personal access token

Expected Behavior

The MCP operation resolves the review thread, matching GitHub GraphQL behavior for the same token.

Actual Behavior

The MCP operation returns a personal-access-token authorization error. Other writes succeeded in the same MCP workflow: inline replies were posted to five pull request review-comment threads.

Direct GraphQL Verification

Using the same fine-grained PAT outside MCP, unresolving the thread succeeded:

GH_TOKEN=github_pat_REDACTED gh api graphql \
  -f query='mutation($threadId: ID!) {
    unresolveReviewThread(input: {threadId: $threadId}) {
      thread { id isResolved }
    }
  }' \
  -f threadId='PRRT_kwDOPgvNY86gGnRD'

Response:

{
  "data": {
    "unresolveReviewThread": {
      "thread": {
        "id": "PRRT_kwDOPgvNY86gGnRD",
        "isResolved": false
      }
    }
  }
}

Resolving it again with the same token also succeeded:

GH_TOKEN=github_pat_REDACTED gh api graphql \
  -f query='mutation($threadId: ID!) {
    resolveReviewThread(input: {threadId: $threadId}) {
      thread { id isResolved }
    }
  }' \
  -f threadId='PRRT_kwDOPgvNY86gGnRD'

Response:

{
  "data": {
    "resolveReviewThread": {
      "thread": {
        "id": "PRRT_kwDOPgvNY86gGnRD",
        "isResolved": true
      }
    }
  }
}

Impact

Agents can reply to inline review feedback but cannot complete the normal review workflow by resolving addressed threads through the hosted GitHub MCP server, despite the configured PAT being authorized for the underlying GraphQL mutation.

Notes

• The token value is intentionally omitted.
• The hosted endpoint does not expose a locally inspectable server version.
• Inline reply timestamps immediately preceding the failure were 2026-09-08T05:35:45Z and 2026-09-08T05:35:46Z.