Getting it into your agent
This one installs as part of its plugin. Adding the marketplace and installing the plugin brings it with everything else the plugin ships.
/plugin marketplace add mishahanin/heading-os-marketplace/plugin install heading-coreWrote 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.
[](https://agentmods.dev/commands/mishahanin/heading-os-marketplace/compact-at)<a href="https://agentmods.dev/commands/mishahanin/heading-os-marketplace/compact-at"><img src="https://agentmods.dev/badge/commands/mishahanin/heading-os-marketplace/compact-at/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.
<a href="https://agentmods.dev/commands/mishahanin/heading-os-marketplace/compact-at"><img src="https://agentmods.dev/badge/commands/mishahanin/heading-os-marketplace/compact-at.svg" alt="Reviewed on agentmods" width="80" height="20"></a>What it costs to keep this loaded
Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5.1 | $0.00017 | $0.00367 |
| Opus 5 | $0.00009 | $0.00183 |
| Sonnet 5 | $0.00003 | $0.00073 |
| Haiku 4.5 | $0.00002 | $0.00037 |
Grade A, and why
compact-at 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 11d ago.
A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.
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.
This is a copy
92% identical to compact-at — 6 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.
What it actually says
Set the compaction threshold for THIS session. Do nothing else.
The argument is $ARGUMENTS. Read the first token only.
- If the token is a whole number,
status, oroff, run that command:
python "${CLAUDE_PLUGIN_ROOT}"/scripts/checkpoint-paths.py --compact-at <token>
- If the argument is empty, run the status command:
python "${CLAUDE_PLUGIN_ROOT}"/scripts/checkpoint-paths.py --compact-at status
- If the token is anything else, print one line:
usage: /compact-at N|status|off. Run no command.
Report the command output in one line. Then stop.
The command refuses a number outside 15-90, and refuses one at or below the session's last rendered fill.
An accepted number also turns unattended on, which turns auto on with it, so
one command is enough and the hook compacts at the threshold instead of asking.
A refusal raises nothing, and status and off raise nothing. When the mode is
already on the command leaves the running stretch alone. Only the operator lowers
it, with /unattended off.
Do NOT write a checkpoint file. Do NOT run /compact. Do NOT continue any task.
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.
- 11d ago First seen · 38 lines · 17 tokens per session scan A ab9f2bdc9b72
compact-at is a command published in the GitHub repository mishahanin/heading-os-marketplace (2 stars, last pushed 4d ago), licensed Apache-2.0. It adds 17 tokens to every session and 367 once invoked, about $0.0001 per session on Opus 5. A static security scan graded it A with 0 findings. It is 92% identical to compact-at, differing in 6 lines, and is treated as a copy.
Other commands, from other repositories
promote
Move .memory/ artifacts to permanent knowledge locations.
checkpoint
Create or update .memory/ with current conversation state.
cleanup
Delete promoted content from the .memory/ directory.
tldr
Compress what was just said into a TLDR. /tldr for the last reply, /tldr session for everything since the session started.
release
Execute the full release workflow for ekstend plugins.
prototype
You are building a proof-of-concept for the current Grainulator sprint. Read CLAUDE.md for sprint context and claims.json for existing research claims.