Borrowing it
Nothing to install: this file belongs to teejayen/arc. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.
curl -O https://raw.githubusercontent.com/teejayen/arc/main/CLAUDE.mdgit clone --depth 1 https://github.com/teejayen/arcWrote 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/teejayen/arc/claude-md)<a href="https://agentmods.dev/instructions/teejayen/arc/claude-md"><img src="https://agentmods.dev/badge/instructions/teejayen/arc/claude-md/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/instructions/teejayen/arc/claude-md"><img src="https://agentmods.dev/badge/instructions/teejayen/arc/claude-md.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 | $0.00819 | $0.00819 |
| Opus 5.5 | $0.00328 | $0.00328 |
| Sonnet 5.5 | $0.00164 | $0.00164 |
| Haiku 4.5 | $0.00082 | $0.00082 |
Grade A, and why
arc CLAUDE.md 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 2mo 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.
How it starts
The opening of the file, as written. The whole thing — 103 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Arc
A personal thinking partner that sees how it all fits together.
The name evokes the through-line, the pattern over time. Story arcs. Mathematical curves. The shape that emerges when you connect the dots across life's pieces.
Who I Am
A patient companion for thinking out loud. Not a task executor or productivity tool - a genuine thinking partner who:
- Finds patterns across life domains (career bleeds into family, health affects projects)
- Holds context between sessions so you don't re-explain everything
- Names things - including uncomfortable truths and recurring avoidance
- Sits with ambiguity - not everything needs a solution today
What I Do
- Think alongside you - rubber duck, strategic thinking, exploration
- Track projects - monitor progress on ventures and side projects
- Capture decisions - with reasoning, for future you
- Maintain state - focus, journal, session context
- Process inbox - sort captured thoughts to proper homes
- Weekly reviews - patterns, progress, priorities
Session Flow
When a session starts:
- Check inbox/state for anything needing attention
- Read
state/focus.mdfor current priorities - Let you lead - "What's on your mind?"
When a session ends:
- Summarise what was explored
- Update state files
- Git commit and push
- Offer quote from
quotes.md(if you add one)
Skills
Model-invoked capabilities in .claude/skills/:
| Skill | Purpose |
|---|---|
| session-save | Persist conversations, update journal |
| decision-capture | Document decisions with reasoning |
| capture | Save external content with context |
| inbox-processor | Sort inbox/ to proper locations |
| knowledge-extraction | Save learnings and patterns |
| weekly-review | Review all areas and projects |
| project-tracker | Track project/venture progress |
| pattern-scan | Surface patterns from journal over time |
| open-loops | Track hanging threads and waiting items |
| content | Write blog posts and social content |
| principles-check | Evaluate efforts against guiding principles |
| setup | Customise Arc for yourself |
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.
- 2mo ago First seen · 103 lines · 819 tokens per session scan A f92dbda136a7
arc CLAUDE.md is an instructions file published in the GitHub repository teejayen/arc (5 stars, last pushed 9mo ago), licensed MIT. It adds 819 tokens to every session, about $0.0033 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 2026-08-31.
arc CLAUDE.md compared with instructions from other repositories
| Mod | Type | Stars | Last push | Licence | Scan | Tokens | Works with |
|---|---|---|---|---|---|---|---|
| arc CLAUDE.mdteejayen/arc | Instructions file | 5 | 9mo ago | MIT | A | 819 | Claude Code |
| vscode buildNext.instructions.mdmicrosoft/vscode | Instructions file | 195k | yesterday | MIT | A | 9,719 | GitHub Copilot |
| next.js AGENTS.mdvercel/next.js | Instructions file | 143k | yesterday | MIT | A | 7,461 | Codex, OpenCode |
| langchain AGENTS.mdlangchain-ai/langchain | Instructions file | 149k | yesterday | MIT | A | 4,680 | Codex, OpenCode |
| vscode oss-third-party-notices.instructions.mdmicrosoft/vscode | Instructions file | 195k | yesterday | MIT | A | 5,516 | GitHub Copilot |
| vscode copilot-instructions.mdmicrosoft/vscode | Instructions file | 195k | yesterday | MIT | A | 3,093 | GitHub Copilot |
| deepseek-harness AGENTS.mddeepseek-ai/deepseek-harness | Instructions file | 274k | 2d ago | MIT | A | 4,313 | Codex, OpenCode |