What is SubagentStart?

A hook that runs a command whenever a subagent starts. In this setup, it launches a Bun program from the fusengine agents package.

Use it to trigger startup automation for subagents, such as loading shared guidance or agent-specific cached context.

It lets the development environment automatically add shared context or setup when work is handed to another agent. The configured dispatcher also routes context by agent type.

SubagentStart — Hook by fusengine

Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

agentmods

npx agentmods add hooks/fusengine/agents/subagent-start

Clone the repo

git clone --depth 1 https://github.com/fusengine/agents

Per session not measured What this adds to a session before it is invoked.

When invoked not measured Not applicable: nothing here is loaded into a session.

Security scan A 0 findings. Scan, not verified.

Origin original No closer match found in the catalogue.

Security

Grade A, and why

SubagentStart scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured yesterday.

A static scan of the commands this hook runs, not an audit. A hook is shell that executes on your machine at the event it names, which is why every command in it is printed with what was found.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

plugins/ai-pilot/hooks/hooks.json · 14 lines

What it actually says

{
  "SubagentStart": [
    {
      "_description": "Single matcher-'' entry: the harness dispatcher (dispatch-aipilot.ts onSubagentStart) already combines apex + lessons + the agent-type-specific cache (explore/doc/test) in ONE call, routing by agent_type internally. Extra per-agent entries here would match ALONGSIDE this one and inject the same context twice.",
      "matcher": "",
      "hooks": [
        {
          "type": "command",
          "command": "bun $HOME/.claude/plugins/marketplaces/fusengine-plugins/plugins/node_modules/@fusengine/harness/dist/cli/bin.mjs hook claude-code aipilot"
        }
      ]
    }
  ]
}

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

yesterday First seen · 14 lines scan A 035b58b669d6

Subscribe to this mod's changes

SubagentStart is a hook published in the GitHub repository fusengine/agents (25 stars, last pushed 28d ago), licensed MIT. Its token cost is not measured: a hook is shell that never enters the context. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.

Building agents Productivity claude-agent claude-agents claude-code claude-code-plugin claude-skills claudecode

SubagentStart

Getting it into your agent

Grade A, and why

Nothing flagged

What it actually says

What this file has done since we first saw it

Other hooks, from other repositories

SubagentStart

SubagentStop

SubagentStop

SubagentStop

SubagentStop

SubagentStop