[BUG] Cowork stays pinned to stale plugin version from custom git marketplace; marketplace cannot be removed or re-added

Preflight Checklist

• [x] I have searched existing issues and this hasn't been reported yet
• [x] This is a single bug report (please file separate reports for different bugs)
• [x] I am using the latest version of Claude Code

What's Wrong?

A new skill added to a plugin in a custom GitHub-hosted marketplace loads correctly in Claude Code CLI but never appears in Claude Cowork (desktop). Cowork continues serving the previous version of the plugin. Attempting to remove and re-add the marketplace in Cowork leaves it in an unrecoverable state: the plugin uninstalls, but the marketplace cannot be removed, and re-adding fails with "marketplace is already installed".

The same repo, same commit, produces the correct result in CLI. This makes the contrast unambiguous.

What Should Happen?

Cowork picks up the new skill after the marketplace is refreshed, matching CLI behaviour. Failing that, removing and re-adding the marketplace should restore a clean state.

Error Messages/Logs

Steps to Reproduce

1. Add a new skill directory skills/command-of-message/SKILL.md to the tech-marketing-skills plugin in the marketplace repo.
2. Bump version in .claude-plugin/plugin.json.
3. Commit and push to main.
4. In Cowork, attempt to pick up the update via the Personal tab in Browse Plugins.
5. Observe the plugin still exposes only the previous five skills.
6. Remove the plugin in Cowork, then attempt to remove the marketplace and re-add it.

Claude Model

None

Is this a regression?

I don't know

Last Working Version

_No response_

Claude Code Version

1.32885.1 (a757f5)

Platform

Anthropic API

Operating System

macOS

Terminal/Shell

Terminal.app (macOS)

Additional Information

Actual Behaviour

CLI (correct):

$ claude plugin marketplace add mwpreston/TechMarketingClaudeSkills
✔ Successfully added marketplace: tech-marketing-claude-skills

$ claude plugin install tech-marketing-skills
✔ Successfully installed plugin: tech-marketing-skills@tech-marketing-claude-skills

$ claude plugin details tech-marketing-skills
Component inventory
  Skills (6)  command-of-message, example-skill, how-it-works,
              review-content, technical-faq, tellmeajoke

Cowork (incorrect): the plugin exposes five skills. command-of-message is absent. Confirmed by inspecting the mounted skills directory inside a Cowork session, which shows only:

tech-marketing-skills:example-skill
tech-marketing-skills:how-it-works
tech-marketing-skills:review-content
tech-marketing-skills:technical-faq
tech-marketing-skills:tellmeajoke

After attempting removal: the plugin is gone, but the marketplace cannot be removed and re-adding fails with "This marketplace is already added". No local file appears to hold this state, so it is not recoverable by the user.

Ruled Out

• Repo structure and frontmatter are valid. CLI loads all six skills from the same commit.
• version was bumped in plugin.json, so this is not version-based deduplication.
• Skill folder is at the plugin root under skills/, not inside .claude-plugin/.
• Frontmatter name matches the directory name.

Impact

This is our team's distribution channel for internal skills. The intended audience is non-engineering colleagues on Cowork, so "use the CLI instead" is not a viable workaround for them. Every skill we add is invisible to the team, and the marketplace is now in a state we cannot repair from our side.

Possibly Related

• #65426 (Cowork cannot update custom git-marketplace plugin; reverts on relaunch)
• #69020 (Cowork installs stale cached plugin version, ignores repo updates)
• #39400 (Marketplace plugins fail to load skills in Cowork; zip upload works)
• #38185 (Personal tab in Browse Plugins fails to load, blocking update controls)
• #9537 (Marketplace removal leaves settings entry behind, blocking re-add)