A pre-compaction hook runs a Bash script just before the agent shortens its working context. It searches known plugin locations for `pre-compact.sh` and runs it.

Running `pre-compact.sh` automatically before context compaction in Codex or related plugin setups.

It lets project-specific preparation happen before context is compacted, so the script can handle work that should occur before details are removed.

PreCompact — Hook by dppdppd

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/dppdppd/rpm/pre-compact

Clone the repo

git clone --depth 1 https://github.com/dppdppd/rpm

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 91% copy Near-identical to another mod 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.

Origin

This is a copy

91% identical to SessionStart — 4 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.

hooks/hooks.json · 12 lines

What it actually says

{
  "PreCompact": [
    {
      "hooks": [
        {
          "type": "command",
          "command": "bash -c 'script=\"$1\"; shift; roots=(); [ -n \"${RPM_PLUGIN_ROOT:-}\" ] && roots+=(\"$RPM_PLUGIN_ROOT\"); [ -n \"${CODEX_PLUGIN_ROOT:-}\" ] && roots+=(\"$CODEX_PLUGIN_ROOT\"); [ -n \"${CLAUDE_PLUGIN_ROOT:-}\" ] && roots+=(\"$CLAUDE_PLUGIN_ROOT\"); roots+=(\"${CODEX_HOME:-$HOME/.codex}/plugins/cache/dppdppd-plugins/rpm/\"* \"${CODEX_HOME:-$HOME/.codex}/plugins/cache/dppdppd-rpm/rpm/\"* \"${CODEX_HOME:-$HOME/.codex}/.tmp/marketplaces/dppdppd-plugins\" \"${CODEX_HOME:-$HOME/.codex}/.tmp/marketplaces/dppdppd-rpm/.codex\"); for root in \"${roots[@]}\"; do [ -f \"$root/hooks/$script\" ] && exec bash \"$root/hooks/$script\"; done; echo \"rpm hook not found: $script\" >&2; exit 127' rpm-hook pre-compact.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.

2d ago First seen · 12 lines scan A 80ba62442d69

Subscribe to this mod's changes

PreCompact is a hook published in the GitHub repository dppdppd/rpm (3 stars, last pushed 3d 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 91% identical to SessionStart, differing in 4 lines, and is treated as a copy.

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PreCompact

Getting it into your agent

Grade A, and why

Nothing flagged

This is a copy

What it actually says

What this file has done since we first saw it

Other hooks, from other repositories

SessionStart

PostToolUse

PreCompact

UserPromptSubmit

PostCompact

Stop