What is SubagentStop?

A completion hook that runs a shell check whenever selected subagents finish.

Use it to trigger the Claude Code Harness stop command after those subagents complete.

It lets a project automatically perform a follow-up validation step after worker, reviewer, or video-scene-generator tasks end.

SubagentStop — Hook by Chachamaru127

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/chachamaru127/claude-code-harness/subagent-stop

Clone the repo

git clone --depth 1 https://github.com/Chachamaru127/claude-code-harness

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 95% copy Near-identical to another mod in the catalogue.

Security

Grade A, and why

SubagentStop 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.

Origin

This is a copy

95% identical to PreToolUse — 47 lines differ, which has more behind it and is treated as the original. This page carries a canonical link to it rather than competing with it.

hooks/hooks.json · 14 lines

What it actually says

{
  "SubagentStop": [
    {
      "matcher": "worker|reviewer|video-scene-generator",
      "hooks": [
        {
          "type": "command",
          "command": "/bin/bash -c 'valid_root(){ local r=\"${1:-}\"; [ -n \"$r\" ] && [ -x \"$r/bin/harness\" ] && [ -f \"$r/.claude-plugin/plugin.json\" ] && /usr/bin/grep -q \"\\\"name\\\"[[:space:]]*:[[:space:]]*\\\"claude-code-harness\\\"\" \"$r/.claude-plugin/plugin.json\"; }; root=\"${CLAUDE_PLUGIN_ROOT:-}\"; if ! valid_root \"$root\"; then root=\"\"; for c in \"${CLAUDE_PROJECT_DIR:-}\" \"$PWD\" \"$HOME/.claude/plugins/marketplaces/claude-code-harness-marketplace\" \"$HOME/.claude/plugins/cache/claude-code-harness-marketplace/claude-code-harness/\"*; do if valid_root \"$c\"; then root=\"$c\"; break; fi; done; fi; if ! valid_root \"$root\"; then echo \"[claude-code-harness] plugin root not found; hook skipped\" >&2; exit 0; fi; exec \"$root/bin/harness\" \"$@\"' _ hook subagent-stop",
          "timeout": 10
        }
      ]
    }
  ]
}

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 410752027626

Subscribe to this mod's changes

SubagentStop is a hook published in the GitHub repository Chachamaru127/claude-code-harness (3,071 stars, last pushed 2d 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. It is 95% identical to PreToolUse, differing in 47 lines, and is treated as a copy.

Building agents Code review

SubagentStop

Getting it into your agent

Grade A, and why

Nothing flagged

This is a copy

What it actually says

What this file has done since we first saw it

Other hooks, from other repositories

SubagentStop

SubagentStop

SubagentStop

Stop

SubagentStart

SubagentStop