agentmods.dev

SubagentStart

A command that runs automatically when a subagent starts. A subagent is a smaller agent launched to handle part of a larger task.

In plain words
What is it for?
Running sync-subagent-start.sh at the start of each subagent session.
Why use it?
It keeps the surrounding system informed when new subagents begin work.

Hook

5 3mo ago A scan tokens not measured original MIT
View the source file backloghq/backlog
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/backloghq/backlog/subagent-start
Clone the repo
git clone --depth 1 https://github.com/backloghq/backlog
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 2d ago.

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.

hooks/hooks.json · 12 lines

What it actually says

{
  "SubagentStart": [
    {
      "hooks": [
        {
          "type": "command",
          "command": "${CLAUDE_PLUGIN_ROOT}/scripts/sync-subagent-start.sh"
        }
      ]
    }
  ]
}
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.

  1. 2d ago First seen · 12 lines scan A d6c66eaa9475

Subscribe to this mod's changes

SubagentStart is a hook published in the GitHub repository backloghq/backlog (5 stars, last pushed 3mo 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 2026-08-31.

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Related

Other hooks, from other repositories

SubagentStart

Runs when a subagent starts, executing on-subagent-start.sh. From Chorus-AIDLC/Chorus.

Chorus-AIDLC/Chorus · not measured

SubagentStop

Runs when a subagent finishes, executing on-subagent-stop.sh. From Chorus-AIDLC/Chorus.

Chorus-AIDLC/Chorus · not measured

SubagentStart

Runs when a subagent starts, executing subagent-start.js via node. From SenMuShare/senmu-buildos.

SenMuShare/senmu-buildos · not measured

SubagentStop

Runs when a subagent finishes, executing subagent-stop.mjs. From arch-team/devpace.

arch-team/devpace · not measured

SubagentStop

Runs when a subagent finishes, executing subagent-stop.sh. From softspark/ai-toolkit.

softspark/ai-toolkit · not measured

TaskCompleted

Runs when a task is marked completed, executing on-task-completed.sh. From Chorus-AIDLC/Chorus.

Chorus-AIDLC/Chorus · not measured