[steve-calvert-glean]

Stacked on #35. Merge that first.

Problem

Codex reads the open Agent Plugins format, and so does GitHub Copilot. Our only Agent Plugins output is the codex target. It publishes to codex-plugins with a Codex-only marketplace, so Copilot users have nothing to install.

Change

This adds an agent-plugins target that builds each plugin once as an Agent Plugins package. It also writes a marketplace for Codex and one for Copilot. On release it publishes to the new gleanwork/glean-plugins repo.

• The packages match the codex target's: the same plugin.json (with Codex's card under extensions["com.openai"]), mcp.json and skills. The Codex interface and marketplace entry values are now shared constants, so the two targets can't drift apart.
• Copilot also gets the ten custom agents, as com.github.copilot/agents/NAME.agent.md.
• overrides/agent-plugins/ holds READMEs with install steps for both clients, plus the Codex override's MCP config and assets.
• validate, the changelog check, publish.yml, README.md and RELEASE.md all cover the new target.

The claude, cursor and codex outputs don't change.

glean-plugins/
├── .agents/plugins/marketplace.json   # Codex
├── .github/plugin/marketplace.json    # Copilot
└── plugins/
    ├── glean/            # plugin.json, mcp.json, mcp/, skills/, com.github.copilot/agents/
    └── glean-dev-docs/   # plugin.json, skills/

Testing

• npm test passes with @gleanwork/pluginpack 0.12.0, and all four targets validate.
• A manual publish.yml run from this branch passed every job and opened gleanwork/glean-plugins#1.
• The new npm run e2e:install passes all 15 checks against that sync branch (--source gleanwork/glean-plugins --ref pluginpack/sync-agent-plugins) and against a local build. In Codex 0.160.1 and Copilot CLI 1.0.100, both plugins install, the 19 glean skills and Copilot's 10 agents are present, and the Glean MCP server answers initialize and tools/list from each client's resolved config.

Still to test before release: a signed-in Copilot session (agents, Glean sign-in, tool calls), VS Code and Cursor.

Open questions

• skill-creation-guide uses the shared version. That version spawns the work-pattern-analyzer and skill-generator agents. Copilot has them, but Codex doesn't. The Codex-only version hands off to $skill-creator instead, which Copilot lacks. The likely fix is a version that uses the agents when they exist and does the work itself otherwise.
• glean-dev-docs still needs a manual mcp add in each client, as it does for Codex today.