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 agentmods add instructions/laude-institute/headlong/agents-mdgit 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/instructions/laude-institute/headlong/agents-md)<a href="https://agentmods.dev/instructions/laude-institute/headlong/agents-md"><img src="https://agentmods.dev/badge/instructions/laude-institute/headlong/agents-md.svg" alt="Measured on agentmods" 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 | $0.01467 | $0.01467 |
| Opus 5 | $0.00733 | $0.00733 |
| Sonnet 5 | $0.00293 | $0.00293 |
| Haiku 4.5 | $0.00147 | $0.00147 |
Grade C, and why
headlong AGENTS.md scanned grade C with 2 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 6d 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.
Downloads and executes remote codehighSupply chain
curl | sh runs whatever the server returns today, which is not necessarily what it returned when this was reviewed.
curl -fsSL https://headlong.ai/install.sh | bash Makes network callslowCapability
Not a fault in itself. Listed so you know the mod talks to something, and to what.
curl -fsSL https://headlong.ai/install.sh | bash How it starts
The opening of the file, as written. The whole thing — 116 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Operating Headlong as a coding agent
This file is for coding agents (Claude Code, Cursor, and similar). It covers installing Headlong without a tty, checking that it is healthy, and the sharp edges that are not obvious from the code.
Naming: Headlong is the agent framework — identities, thinkers, the
mind log, bridges, the dash. shellm is one tool inside it: the
CLI implementation of Recursive Language Models in bash (bin/shellm),
plus its run machinery (shellm-docker, shellm-explore). Use "Headlong"
for the system and "shellm" only for that tool. Framework commands are
headlong-* (headlong-init, headlong-web, ...; the old shellm-* names
remain as symlinks) and framework env vars are HEADLONG_* (legacy
SHELLM_* spellings still honored). The state home defaults to
~/.headlong, falling back to ~/.shellm when only that exists (so
pre-rename installs keep their state); explicit HEADLONG_HOME or
SHELLM_HOME overrides both. Systemd units are headlong-*; a box provisioned before
the rename is migrated once with deploy/migrate-units.sh (see
deploy/DEPLOY.md). What deliberately keeps the shellm name: the
/opt/shellm deploy path, the shellm and shellm-telegram UNIX users,
~shellm/.shellm, the per-identity .shellm/ subdirectory, the
~/.headlong-thinkers template dir that install.sh seeds, and the
*.shellm.net domains. If you take one of those on, or any other
structural change to a live box, read deploy/MIGRATIONS.md first — it
lists the couplings that fail silently.
Headlong creates a persistent identity whose mind is a loop of LLM calls
run by a dispatcher. The identity has a name (default ada), and that
name becomes a shell command. A local web dashboard shows the mind's
trajectory.
Install without a tty
With no tty the installer asks nothing; every answer comes from an environment variable or a default. A key must be in the environment:
export OPENROUTER_API_KEY=sk-or-... # or ANTHROPIC_/OPENAI_/GEMINI_API_KEY
curl -fsSL https://headlong.ai/install.sh | bash
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.
- 6d ago First seen · 116 lines · 1,467 tokens per session scan C cb88981be5d1
headlong AGENTS.md is an instructions file published in the GitHub repository laude-institute/headlong (1,119 stars, last pushed today), licensed Apache-2.0. It adds 1,467 tokens to every session, about $0.0073 per session on Opus 5. A static security scan graded it C with 2 findings (downloads and executes remote code, makes network calls). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.
Other instructions, from other repositories
codex AGENTS.md
AGENTS.md instructions for openai/codex, covering rust/codex-rs, the codex-core crate, code review rules, crate api surface and model visible context.
vscode buildNext.instructions.md
Working notes and architecture documentation for the new esbuild-based build system in build/next. Use when making changes to the new build pipeline (transpile/bundle commands, NLS plugin, source-map handling, resource copying, or self-hosting watch tasks).
spec-kit AGENTS.md
AGENTS.md instructions for github/spec-kit, covering agents.md, about spec kit and specify, quickstart — add a new integration in 5 steps, integration architecture and integrationmanifest — file tracking.
next.js AGENTS.md
AGENTS.md instructions for vercel/next.js, covering next.js development guide, codebase structure, monorepo overview, core package: packages/next and other important packages.
langchain AGENTS.md
AGENTS.md instructions for langchain-ai/langchain, covering global development guidelines for the langchain monorepo, corridor security analysis, project architecture and context, monorepo structure and development tools & commands.
vscode oss-third-party-notices.instructions.md
Instructions for microsoft/vscode, covering vs code oss third-party-notices pipeline, architecture, pipeline flow in ci, applying the notice (cutover) and fallback chain (never fail the build).