shellm

shellm is a skill for Claude Code, Codex from laude-institute/headlong. It costs 49 tokens per session (2,029 once invoked), scanned A, original, Apache-2.0.

A reference guide to shellm, a collection of Bash scripts that lets an AI model operate in a command-line shell. It covers the system's command-line tools, agent identities, memory, skills, goals, and activity history.

In plain words
What is it for?
Use it when developing shellm, debugging its agent behavior, or tracing how its shell loop, memory, identities, and other tools work.
Why use it?
It gives developers one place to understand how shellm's parts fit together when the written guide may not match the current code.

Skill for Claude CodeCodex

Written for no agent in particular: nothing here depends on one.

Good fit Use it when developing shellm, debugging its agent behavior, or tracing how its shell loop, memory, identities, and other tools work.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/laude-institute/headlong/shellm
About the project

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.

laude-institute/headlong · 1,227 stars · on GitHub · headlong.ai

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.

Any agent
npx skills add laude-institute/headlong --skill shellm
Clone the repo
git clone --depth 1 https://github.com/laude-institute/headlong

Made for: Claude Code, Codex.

Wrote 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.

agentmods badge for shellm

README.md
[![agentmods](https://agentmods.dev/badge/skills/laude-institute/headlong/shellm/github.svg)](https://agentmods.dev/skills/laude-institute/headlong/shellm)
Your own site
<a href="https://agentmods.dev/skills/laude-institute/headlong/shellm"><img src="https://agentmods.dev/badge/skills/laude-institute/headlong/shellm/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.

agentmods 80×15 button for shellm

Your own site · 80×15
<a href="https://agentmods.dev/skills/laude-institute/headlong/shellm"><img src="https://agentmods.dev/badge/skills/laude-institute/headlong/shellm.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 49 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 2,029 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe. Third-party audits
  • NVIDIA SkillSpector warn 7 Sept 2026
SkillSpector: 1 finding, up to high

These are SkillSpector’s own severities. On a checked sample its high-severity flags on skills were ~96% false positives — a documented command, a public API, a “never do X” rule — so we show them as a caution to read, not a verdict. Why →

  • high Privilege Escalation · line 122
    Code accesses credential files (SSH keys, AWS credentials, etc.). This could indicate credential theft attempts.
    Fix: Remove references to credential paths. Use environment variables or secrets managers. For docs, use placeholder paths (e.g., /path/to/config). Never load .env or token files in production code paths.
How audits are shown
Origin original No closer match found in the catalogue.
Token cost

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.

ModelPer sessionOnce invoked
Fable 5.1 $0.00049 $0.02029
Opus 5.5 $0.00020 $0.00812
Sonnet 5.5 $0.00010 $0.00406
Haiku 4.5 $0.00005 $0.00203

Measured 1mo ago against content hash ad6ec193260e, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

shellm 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 1mo 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.

skills/shellm/SKILL.md · 165 lines

How it starts

The opening of the file, as written. The whole thing — 165 lines — stays where its author put it; the contents beside it link to each section on GitHub.

shellm

This skill may be out of date. The source of truth is always the code in bin/. If you find discrepancies, use the skill-author skill to update this file and open a PR.

Architecture overview

shellm is a set of composable bash scripts that turn an LLM into an autonomous agent living in a shell. The stack, bottom to top:

llm              raw LLM calls (Anthropic, OpenAI, Gemini)
shellm           recursive execute-in-shell loop on top of llm
traj / context   step log (DAG) + message assembly for multi-turn
mem / skills     persistent memory + learnable capabilities
identity         isolated agent identities (own mem, skills, traj)
think / chat     autonomous thinking + human conversation
focus            goal tracking

An agent activates an identity (source .identities/<name>/activate), which sets env vars. All tools read from those env vars — no global config files.

bin/ reference

Core engine

Script Purpose
shellm Recursive LLM-in-bash loop. Sends a prompt to the LLM, executes returned bash code blocks, feeds output back, repeats until FINAL is set. The heart of the system.
llm Multi-provider LLM CLI. llm [options] prompt or stdin. Supports Anthropic, OpenAI, Gemini. Key flags: -m MODEL, -s SYSTEM, -M MESSAGES_JSON, --stream, --thinking.

Identity & activation

Script Purpose
identity Manage isolated identities. Each has its own memories, skills, kernel, traj. Subcommands: new, list, info, switch, delete, shell, prompt.

Activate an identity to set env vars for all other tools:

source .identities/myagent/activate   # activate in current shell
deactivate_identity                    # undo
identity shell myagent                 # or: start a subshell

Thinking & conversation

Script Purpose
think One autonomous think cycle. Reads traj + memories, calls shellm with think prompt, writes thought/action to traj, dispatches thought processes. think step [--dry-run].
chat Send messages into the thought stream. chat send <msg> appends a human-msg step. chat repl gives a readline loop.
focus Goal management. focus set <goal>, focus show, focus done <query>. Stores goals as mem entries with type=goal.

Read the full file on GitHub · 165 lines

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. 1mo ago First seen · 165 lines · 49 tokens per session scan A ad6ec193260e

Subscribe to this mod's changes

shellm is a skill published in the GitHub repository laude-institute/headlong (1,227 stars, last pushed today), licensed Apache-2.0. It adds 49 tokens to every session and 2,029 once invoked, about $0.0002 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 2026-08-30.

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