Keep the gh-stack agent skill in sync with CLI releases via packslip #618

Summary

Publish packslip release metadata that declares the existing gh-stack agent skill, so installers such as mise can keep the skill aligned with the installed CLI version.

Description

gh-stack already provides an agent skill, but it requires installation separately from the CLI. Updating the CLI and updating the skill are therefore separate operations, which can leave an agent following instructions from a different release.

Packslip lets release publishers describe their binaries and supporting resources, including agent skills. Mise supports these declarations: it fetches the skill for the installed tool version and can update the agent’s skill links automatically when the tool is upgraded, if automatic syncing is enabled.

The current release workflow publishes binaries without packslip metadata, so this would require adding packslip publishing as well as the skill declaration.

Proposed implementation plan

1. Extend the release workflow to publish packslip metadata for the existing gh-stack binaries.

2. Declare the full skills/gh-stack directory as a skill resource, pinned to the same source commit as the CLI release:

   skill/gh-stack=repo:skills/gh-stack
   

   Include both SKILL.md and its supporting reference files. See Packslip’s agent skill documentation.

3. Document how users installing gh-stack through mise’s packslip backend can discover and sync the skill, including automatic syncing.

4. Verify that mise lists the skill for the installed gh-stack version and that changing versions followed by a sync selects the corresponding skill files.