M03 RECON: prove official MCP standard write with branch creation

[GBOGEB]

Mission

M03_GITHUB_MCP_SERVER / P_M03_OFFICIAL_BRANCH_WRITE_01

Objective

Advance from two live read families to one real low-risk standard write mutation through the exact official MCP server.

Controlled mutation

• exact official source: github/github-mcp-server@7d13a7ad6f2a17f351a6d77ce280c85ae1821f4d;
• toolset/tool: repos/create_branch;
• target: GBOGEB/github-mcp-server;
• source branch: main;
• created branch: unique probe/m03-official-write-${GITHUB_RUN_ID};
• no file/content mutation and no QPS semantic change.

FIRST RED discipline

Only recurse on the first observed step: runner -> exact checkout -> build -> schema -> permission/API mutation -> response binding -> receipt.

Authority boundary

GREEN proves one standard GitHub write operation through official MCP transport. It does not prove all write tools, all auth modes, or Governor/DoV semantics. QPS remains the control/evidence plane.

[chatgpt-codex-connector]

Codex Review Summary

This comment shows the latest Codex review activity on this pull request.

Review	Status	Commit	Review trigger
📝 Code Review	✅ Completed 2026-09-11T16:43:52.511098Z	bffce38	PR opened

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[chatgpt-codex-connector]

💡 Codex Review

Here are some automated review suggestions for this pull request.

Reviewed commit: bffce38c7f

ℹ️ About Codex in GitHub

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• Open a pull request for review
• Mark a draft as ready
• Comment "@codex review".

If Codex has suggestions, it will comment; otherwise it will react with 👍.

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[chatgpt-codex-connector]

Restrict the write probe to trusted pull requests

For pull requests originating from forks (including Dependabot-style fork contexts), GitHub downgrades github.token to read-only despite the requested contents: write permission. Because this workflow runs for every PR targeting main, the later create_branch call against GBOGEB/github-mcp-server will fail for external contributions; gate the job to same-repository PRs or reserve this mutation for workflow_dispatch.

Useful? React with 👍 / 👎.

[chatgpt-codex-connector]

Include the run attempt in the probe branch name

When this workflow is rerun, GITHUB_RUN_ID remains unchanged, so any first attempt that reached branch creation leaves this exact ref behind. A rerun—particularly after a later artifact or receipt step failed—then receives an already-exists error from create_branch and can never recover; include GITHUB_RUN_ATTEMPT in the name or make existing-branch handling idempotent.

Useful? React with 👍 / 👎.