What is SubagentStart?

A hook configuration that runs a Node.js script whenever a subagent starts. A subagent is an additional AI worker launched to handle part of a task.

Use it to configure the SubagentStart event with a session-start script and a short execution timeout.

It lets a project run a defined startup action automatically for each newly started subagent, rather than relying on manual setup.

SubagentStart — Hook by DanielGouveiah

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/danielgouveiah/glasses/subagent-start

Clone the repo

git clone --depth 1 https://github.com/DanielGouveiah/glasses

Or install glasses, the plugin that ships this one along with the rest of its 3 skills, 2 hooks.

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 3d 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.

skills/glasses/hooks/hooks.json · 18 lines

What it actually says

{
  "SubagentStart": [
    {
      "hooks": [
        {
          "type": "command",
          "command": "node",
          "args": [
            "${CLAUDE_PLUGIN_ROOT}/scripts/session-start.mjs",
            "SubagentStart"
          ],
          "timeout": 10,
          "statusMessage": "Loading Glasses mode"
        }
      ]
    }
  ]
}

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.

3d ago First seen · 18 lines scan A 5e5c9106c2a4

Subscribe to this mod's changes

SubagentStart is a hook published in the GitHub repository DanielGouveiah/glasses (9 stars, last pushed 13d 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.

ai-agents architecture claude-code developer-tools yagni

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

PostToolUse

SessionStart

SessionStart

SessionStart

PreToolUse

Stop