Release script: agent-written summary in the bump PR #159

Parent

#150

What to build

An agent writes the bump PR's summary, in place of GitHub's generated notes.

Input. The release script collects:

• the version diff
• the title, number and body of each PR merged since the last v* tag, leaving out the bump PR

It pipes these to claude -p with tools disabled, after a prompt kept as a file in the repo next to the script.

What the prompt asks for:

• A short headline paragraph on what the release is about.
• What changes for someone running thirdshift first: new commands, and behaviour that is new or changed.
• Site, docs and CI work in one short grouped line.
• Every change referenced by its PR number.
• Nothing claimed beyond what the PR titles and bodies say.

The #100 summary for 0.3.0 ("the headline is the Merge run…") is the model.

Output. The agent's output fills the PR body's summary section, followed by the version diff, which the script still writes.

Fallback. If the agent fails (non-zero exit, empty output, not logged in), the script warns on stderr and fills the summary section with GitHub's generated notes, preceded by a one-line note that the agent summary was unavailable. It then carries on.

Acceptance criteria

• The fake claude receives the prompt file's content plus exactly the collected input: the version diff and each merged PR's title, number and body, with the bump PR left out.
• claude is invoked in print mode with tools disabled.
• The PR body's summary section holds the agent's output, followed by the version diff.
• When the fake claude fails or prints nothing, the summary section holds the fallback note and the generated notes, a warning goes to stderr, and the release carries on to the tag.
• The prompt file carries the emphasis rules above.

Blocked by

• Release script: one command from version to pushed tag #156