Cairn Help

A help guide for Cairn, a set of tools and commands for recording decisions, checking context, and handing work between sessions. It responds to phrases such as “Cairn Help” and “Cairn resume.”

In plain words
What is it for?
Use it when someone asks what Cairn can do, wants to resume from its decision record, save a handoff, or check host and context status.
Why use it?
It gives users one short reference for Cairn’s trigger phrases, tools, and terminal commands instead of requiring them to remember each one.

Skill for Claude CodeCodex

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 skills/cheswickdev/cairn/cairn-help
Any agent
npx skills add CheswickDEV/cairn --skill cairn-help
Clone the repo
git clone --depth 1 https://github.com/CheswickDEV/cairn

Made for: Claude Code, Codex.

Per session 63 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 553 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
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 $0.00063 $0.00553
Opus 5 $0.00032 $0.00277
Sonnet 5 $0.00013 $0.00111
Haiku 4.5 $0.00006 $0.00055

Measured yesterday against content hash 2eee437d7e6d, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

Cairn Help 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 yesterday.

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.

.agents/skills/cairn-help/SKILL.md · 38 lines

What it actually says

Cairn Help — quick reference

When the user says "Cairn Help" (or asks what Cairn can do), show this overview verbatim:

Trigger phrases — say these in chat, the agent acts

Say… What happens
Cairn resume Re-inject the ledger (decision_log view=current) and continue from it as the source of truth — without re-reading the repo.
Cairn Handoff Author a 7-bucket brief from the conversation and persist it via handoff (local, no egress).
Cairn Help Show this table.

MCP tools — the agent calls these directly (Codex has no statusline/hooks, so call them yourself)

Tool Purpose
decision_log Read / re-inject the ledger. view:"current" = lean resume state; view:"all" = full history + evidence.
handoff Persist a host-written 7-bucket brief (account mode = no model call, nothing leaves the host).
context_status Report the zone (🟢/🟡/🔴) relative to the active window (pass the host model_context_window, e.g. 258400, as surfaceCap).
host_status Which host CLIs are logged in + the active model.

Shell command — you, in the terminal

Command What it shows
cairn status One-line zone of the active Codex session (e.g. 🟢 21% ctx · gpt-5.5).
cairn window Live zone strip as a split pane (Windows Terminal / tmux / iTerm2).
cairn tab / cairn stop Zone in the terminal title / stop it.
cairn list All recent Codex sessions (pin one with --session <uuid>).

Cairn is a local-private continuity engine: it persists decisions + evidence across sessions/models and warns before the context window degrades. In the default account mode nothing leaves the host.

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. yesterday First seen · 38 lines · 63 tokens per session scan A 2eee437d7e6d

Subscribe to this mod's changes

Cairn Help is a skill published in the GitHub repository CheswickDEV/cairn (1 stars, last pushed 2mo ago), licensed MIT. It adds 63 tokens to every session and 553 once invoked, about $0.0003 per session on Opus 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 2026-08-31.