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 skills/cairn-framework/cairn/cairn-devnpx skills add cairn-framework/cairn --skill cairn-devgit clone --depth 1 https://github.com/cairn-framework/cairnWhat 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 | $0.00063 | $0.00907 |
| Opus 5 | $0.00032 | $0.00453 |
| Sonnet 5 | $0.00013 | $0.00181 |
| Haiku 4.5 | $0.00006 | $0.00091 |
Grade A, and why
cairn-dev 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 2d 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.
Copies of this mod
1 near-identical copy found in the catalogue:
- cairn-dev — 100% identical, 0 lines differ
How it starts
The opening of the file, as written. The whole thing — 85 lines — stays where its author put it; the contents beside it link to each section on GitHub.
cairn-dev
This repository declares its architecture in cairn.blueprint; cairn reconciles
that declaration against the code and reports the gap. This file is a router:
load the one reference your task needs, and only that one.
Authority
The target repository outranks this guide: its AGENTS.md, CLAUDE.md, and
CONTRIBUTING.md decide conventions, gates, and workflow, and accepted
decisions in the graph (cairn rationale <node>) bind the nodes they name.
Where this guide disagrees with either, this guide is wrong.
First move
cairn context
It returns the nodes, edges, artefacts, and current findings, and names the
node that owns the area you were asked about. Run it before opening files.
Orient from the queries, never from map.json or map.md: those are generated
review snapshots for humans reading a diff, not agent context.
The gate
cairn scan # zero findings is the target
cairn hook all # exit 0 means the commit is safe
Run both before you hand work back. Fix the cause of an Error finding. Never bypass a hook.
Routes
Match the session to one row and load only that reference. Paths are relative to this file.
| The task is | Load |
|---|---|
| Find why something misbehaves, then fix it | references/task-bug-investigation.md |
| Restructure code without changing behaviour | references/task-refactoring.md |
| Understand how a system fits together | references/task-architecture-discovery.md |
| Build something new, or extend a module | references/task-feature-implementation.md |
| Mine an existing codebase into proposed decisions | references/task-brownfield-decision-extraction.md |
Write or edit cairn.blueprint |
references/blueprint-syntax.md |
| Interpret a finding code | references/finding-codes.md |
| Write a decision, research, source, or todo | references/artefact-schemas.md |
| Look up a command or flag | references/command-reference.md |
| Navigate the graph, read source through it, or resolve a node id | references/graph-navigation.md |
| Run one full cairn development iteration | references/loop-mode.md, if installed, and only on explicit request (see below) |
What ships with it
11 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.
- references/artefact-schemas.md 5.8 KB
- references/blueprint-syntax.md 4.5 KB
- references/command-reference.md 5.1 KB
- references/finding-codes.md 5.7 KB
- references/graph-navigation.md 3.3 KB
- references/loop-mode.md 16 KB
- references/task-architecture-discovery.md 2.2 KB
- references/task-brownfield-decision-extraction.md 5.8 KB
- references/task-bug-investigation.md 1.8 KB
- references/task-feature-implementation.md 2.6 KB
- references/task-refactoring.md 1.9 KB
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.
- 2d ago First seen · 85 lines · 63 tokens per session scan A c5dc9daf7559
cairn-dev is a skill published in the GitHub repository cairn-framework/cairn (40 stars, last pushed 2d ago), licensed Apache-2.0. It adds 63 tokens to every session and 907 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 2026-08-30.
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