A pre-compaction hook that checks whether the Git working directory has uncommitted changes before the coding session's context is shortened. Git is the version-control system commonly used to track code changes.

Use it to check for uncommitted changes immediately before context compaction and display a reminder when they exist.

It warns you that work may not be committed before session details are compacted, reducing the chance of overlooking unfinished changes.

PreCompact — Hook by derjochenmeyer

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/derjochenmeyer/claude-code-craft/pre-compact

Clone the repo

git clone --depth 1 https://github.com/derjochenmeyer/claude-code-craft

Made for: Claude Code.

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

PreCompact 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.

.claude/settings.json · 14 lines

What it actually says

{
  "PreCompact": [
    {
      "matcher": "",
      "hooks": [
        {
          "type": "command",
          "command": "git diff --quiet HEAD 2>/dev/null && printf '{\"decision\":\"allow\"}' || printf '{\"decision\":\"allow\",\"systemMessage\":\"[craft] Uncommitted changes detected. Consider committing before compaction to preserve this session.\"}'",
          "timeout": 5
        }
      ]
    }
  ]
}

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 e4bb6ac11ab8

Subscribe to this mod's changes

PreCompact is a hook published in the GitHub repository derjochenmeyer/claude-code-craft (2 stars, last pushed 4mo 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.

Git and workflow

PreCompact

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

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