Headlong is a Bash-based agent microharness for running language-model agents in persistent, self-directed loops. People use it to create agents that maintain ongoing interests and projects, interact through shell commands, and share one stream of conversations across a team and chat services.
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.
npx skills add laude-institute/headlong --skill skill-compilergit clone --depth 1 https://github.com/laude-institute/headlongWrote 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/skills/laude-institute/headlong/skill-compiler)<a href="https://agentmods.dev/skills/laude-institute/headlong/skill-compiler"><img src="https://agentmods.dev/badge/skills/laude-institute/headlong/skill-compiler/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/skills/laude-institute/headlong/skill-compiler"><img src="https://agentmods.dev/badge/skills/laude-institute/headlong/skill-compiler.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 | $0.00025 | $0.00437 |
| Opus 5.5 | $0.00010 | $0.00175 |
| Sonnet 5.5 | $0.00005 | $0.00087 |
| Haiku 4.5 | $0.00003 | $0.00044 |
Grade A, and why
skill-compiler scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured today.
A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.
Nothing flagged
None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.
What it actually says
skill-compiler
Use when developing a trusted skill or checking its documented behavior. Requires Bash, Python 3, jq, llm, shellm, and skills. Model calls use normal llm configuration and can incur charges. This produces validation reports, not trained adapters or automatically loaded examples.
sc="${SKILLS_DIR:-./.skills}/skill-compiler/skill-compiler"
"$sc" compile --skill shellm --num-tests 3 --max-iterations 5
"$sc" show --skill shellm
"$sc" pool --skill shellm
"$sc" clean --skill shellm
This skill requires explicit installation; default agents do not receive it.
The executable is not on PATH. See README.md for installation and
source-checkout usage. Use --teacher-model only to
override the teacher's configured model. Defaults are up to eight cases and fifteen
iterations per case.
Both compile and pool can execute a skill script with no arguments and with --help. Probes and tests use disposable state and work directories. Known messaging/live-store skills and aliases are refused. This is not an OS sandbox: only run trusted skills, since credentials and filesystem access are not revoked.
Inspect the JSON report's summary.fail as well as the exit status. Runner or setup failures return nonzero. Assertions require a successful runner and the named evidence from its actual root run. VERIFIED means the passing literals are attested in the offered vocabulary, not that the test proves useful behavior. Review generated cases and include negative examples.
Reports persist under /skill-compiler/compiled, outside the skill installation. See README.md for outcome semantics, report fields, isolation limits, and optional pool/cache controls.
What ships with it
2 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.
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.
- today First seen · 45 lines · 25 tokens per session scan A db46a964d285
skill-compiler is a skill published in the GitHub repository laude-institute/headlong (1,227 stars, last pushed yesterday), licensed Apache-2.0. It adds 25 tokens to every session and 437 once invoked, about $0.0001 per session on Opus 5.5. 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 2026-10-24.
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