PreCompact

A hook that saves session notes with the memo command before the conversation context is shortened.

In plain words
What is it for?
Use it to force a memo capture at the compaction boundary and write newly captured information to Markdown files.
Why use it?
It reduces the chance that useful insights from a long coding session are lost when older conversation details are compacted.

Hook

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/jagoff/memo/pre-compact
Clone the repo
git clone --depth 1 https://github.com/jagoff/memo
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 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 · 15 lines

What it actually says

{
  "PreCompact": [
    {
      "hooks": [
        {
          "type": "command",
          "command": "MEMO_NONINTERACTIVE=1 memo capture-tick --force",
          "timeout": 60,
          "async": true,
          "comment": "Force-flush the capture throttle window at the compaction boundary so a long session's insight reaches .md before early-session texture is destroyed. Idempotent vs the settings.json copy: run_capture_incremental holds a per-session flock and the watermark makes the second firing a no_new no-op. The transcript JSONL survives compaction, so async is safe."
        }
      ]
    }
  ]
}
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 · 15 lines scan A 7dfc0a1f437f

Subscribe to this mod's changes

PreCompact is a hook published in the GitHub repository jagoff/memo (16 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. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.