briefing — Claude Code plugin: preload subagent skills
A plugin that reads the skills a subagent declares and puts them into its context before the agent starts working.
/plugin marketplace add anthropics/claude-plugins-community
/plugin install briefing@claude-communityWhat briefing does
Subagents begin with a clean context window, and skills load lazily: what sits there is a list of names and descriptions. An agent spawned for a specific piece of expertise still has to notice it needs that expertise. Sometimes it does, sometimes it works uninformed, and the output looks the same either way.
briefing removes the guesswork. At spawn time a hook reads the declaration, resolves each skill and injects the full text. In Claude the hook fires on PreToolUse for the Agent tool, and the declaration lives in a briefing: block in the frontmatter of .claude/agents/*.md. Each skill arrives inside its own <skill name=... dir=...> element; dir points at the folder, so references/ and scripts/ stay on disk and load on demand.
A declared skill that cannot be resolved stops the spawn — the plugin will not run on a partial briefing. Run briefing-doctor to check declarations ahead of time: it walks every agent in the project and exits 1 if any spawn would fail, which makes it usable in CI. Skill names resolve the same way everywhere. A bare name searches project skills, then user skills, then installed plugins; a namespaced one such as superpowers:brainstorming goes straight to that plugin. A marketplace plugin that is off in enabledPlugins resolves to nothing.
What it helps with
- get the right skills into a subagent before it starts
- drop "load skill X first" instructions from the agent body
- catch a misspelled skill name before a spawn fails
- check every agent declaration in CI
- see which skills and how many kilobytes an agent received
Example prompts for the agent
- Add a
briefing:block withgetty-perl-coreandsuperpowers:brainstormingto.claude/agents/reviewer.md - Run
briefing-doctorand show me which agents would fail to spawn - Why did the
backendagent not receive thekubernetes-restskill?
How to install briefing
Plugin marketplace
/plugin marketplace add anthropics/claude-plugins-community/plugin install briefing@claude-communityStep by step, with commands for each platform: Claude Code plugins: marketplaces, installing, and building your own
Questions about briefing
How do I install briefing in Claude Code?
From the marketplace: run /plugin marketplace add anthropics/claude-plugins-community, then /plugin install briefing@claude-community.
What does briefing do?
A hook reads the skills a subagent declares and injects their text into the agent's context at spawn time. If a skill cannot be found, the spawn is denied.
How do I declare skills for an agent?
In Claude, add a briefing: block with a skills field to the frontmatter of .claude/agents/*.md. Names can be bare or namespaced by plugin.
