SubagentStart

SubagentStart is a hook for Claude Code from memgraph/ai-toolkit. Its token cost is not measured, scanned A, a copy of SessionStart, MIT.

A subagent-start hook that runs a context-graph command whenever a subagent begins work.

In plain words
What is it for?
It is for linking subagent activity with context graphs for skills, actions, and sessions.
Why use it?
It automatically records or connects session, action, and skill context without a manual command.

Hook for Claude Code

Written for Claude Code: shipped in a Claude Code plugin.

Part of the context-graph plugin — 1 skill, 13 hooks, 1 MCP server shipped together

One of 13 entries in hooks.json upstream. Installing this one merges just its entry into your config; the other 12 are separate, each on its own page.

Good fit It is for linking subagent activity with context graphs for skills, actions, and sessions.

Compare 6 hooks from other repositories ↓
Install with agentmods
npx agentmods add hooks/memgraph/ai-toolkit/subagent-start
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.

Clone the repo
git clone --depth 1 https://github.com/memgraph/ai-toolkit

Made for: Claude Code.

Or install context-graph, the plugin that ships this one along with the rest of its 1 skill, 13 hooks, 1 MCP server.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

agentmods badge for SubagentStart

README.md
[![agentmods](https://agentmods.dev/badge/hooks/memgraph/ai-toolkit/subagent-start/github.svg)](https://agentmods.dev/hooks/memgraph/ai-toolkit/subagent-start)
Your own site
<a href="https://agentmods.dev/hooks/memgraph/ai-toolkit/subagent-start"><img src="https://agentmods.dev/badge/hooks/memgraph/ai-toolkit/subagent-start/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

agentmods 80×15 button for SubagentStart

Your own site · 80×15
<a href="https://agentmods.dev/hooks/memgraph/ai-toolkit/subagent-start"><img src="https://agentmods.dev/badge/hooks/memgraph/ai-toolkit/subagent-start.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
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. A grade says what 26 rules found in the file — not that it is safe.
Origin 92% copy Near-identical to another mod 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 4d 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.

Origin

This is a copy

92% identical to SessionStart — 2 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.

context-graph/plugins/memgraph-context-graph-claude/hooks/hooks.json · 13 lines

What it actually says

{
  "SubagentStart": [
    {
      "hooks": [
        {
          "type": "command",
          "command": "memgraph-context-graph hook run claude-code --connector skills-graph --connector actions-graph --connector sessions-graph",
          "timeout": 30
        }
      ]
    }
  ]
}
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. 4d ago Changed 655f23a7ee29
  2. 1mo ago First seen · 13 lines scan A 933aeb499f9a

Subscribe to this mod's changes

SubagentStart is a hook published in the GitHub repository memgraph/ai-toolkit (116 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 92% identical to SessionStart, differing in 2 lines, and is treated as a copy.