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/edition-x/arcane/claude-mdgit clone --depth 1 https://github.com/Edition-X/arcaneWhat 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 | $0.01078 | $0.01078 |
| Opus 5 | $0.00539 | $0.00539 |
| Sonnet 5 | $0.00216 | $0.00216 |
| Haiku 4.5 | $0.00108 | $0.00108 |
Grade A, and why
arcane 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 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.
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.
Arcane — Project Instructions for Claude Code
What This Project Is
Arcane is a personal engineering memory MCP server. It exposes tools for saving/searching memories, tracking decision journeys, ingesting artifacts from CI/Linear/Git, and generating blog posts or ADRs. The canonical data store is SQLite with FTS5 + sqlite-vec for hybrid search.
MCP Server
The MCP server is the primary interface for AI agents. Run it with:
arcane mcp
It communicates via stdio (JSON-RPC). For Claude Desktop / Claude Code integration, add it to your MCP config:
{
"mcpServers": {
"arcane": {
"command": "arcane",
"args": ["mcp"]
}
}
}
Development Priorities
- No regressions: always run
pytestbefore committing - Type safety: new public functions must have type annotations; run
mypy src/arcaneafter changes - DRY: check existing services and repos before adding new logic
- Test at boundaries: mock DB and network at the service/repo boundary, not deep inside
Arcane Memory Discipline (for Claude Code)
Arcane is the persistent memory system for this project. Use it automatically — do not wait to be asked.
At the start of every session
- Call
memory_contextfor the current project to load recent decisions, bugs, and context. - If the request references prior work, past decisions, or "last time", call
memory_searchwith task-specific terms. - If the task sounds like an ongoing investigation or spike, call
journey_listto find active journeys.
Before researching anything
- Call
memory_searchfirst — the answer may already be stored.
When to save memories (after every git commit)
- Decision made →
memory_savewithcategory: "decision" - Bug fixed →
memory_savewithcategory: "bug", including root cause and how to recognise it - Pattern discovered →
memory_savewithcategory: "pattern"or"learning" - Milestone shipped →
memory_savewithcategory: "milestone"
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 · 103 lines · 1,078 tokens per session scan A dff7763ebb7e
arcane CLAUDE.md is an instructions file published in the GitHub repository Edition-X/arcane (0 stars, last pushed 27d ago), licensed MIT. It adds 1,078 tokens to every session, about $0.0054 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.
Other instructions, from other repositories
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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.
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.
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).
next.js AGENTS.md
Instructions for vercel/next.js, covering next.js development guide, codebase structure, monorepo overview, core package: packages/next and other important packages.