Borrowing it
Nothing to install: this file belongs to terrene-foundation/metis. 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/terrene-foundation/metis/main/.claude/skills/30-claude-code-patterns/SKILL.mdgit clone --depth 1 https://github.com/terrene-foundation/metisWrote 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/skills/terrene-foundation/metis/30-claude-code-patterns)<a href="https://agentmods.dev/skills/terrene-foundation/metis/30-claude-code-patterns"><img src="https://agentmods.dev/badge/skills/terrene-foundation/metis/30-claude-code-patterns.svg" alt="Measured on agentmods" 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 | $0.00034 | $0.01297 |
| Opus 5 | $0.00017 | $0.00648 |
| Sonnet 5 | $0.00007 | $0.00259 |
| Haiku 4.5 | $0.00003 | $0.00130 |
Grade A, and why
claude-code-patterns 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 3d 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 — 142 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Claude Code Architecture Patterns
Reference patterns for designing effective Claude Code artifacts and understanding CC's internal architecture.
Quick Reference: Artifact Types
| Type | Layer | Purpose | Token Target | Quality Test |
|---|---|---|---|---|
| Agent | L1 Intent | Teach judgment + procedure | 150-400 lines | Completes task without clarification |
| Skill | L2 Context | Teach knowledge + reference | 150-250 lines (SKILL.md) | Answers 80% of routine questions |
| Rule | L3 Guardrails | Enforce boundaries | 50-150 lines | Zero violations in scope |
| Command | L4 Instructions | Orchestrate workflows | 50-150 lines | Predictable, verifiable output |
| Hook | L3 Guardrails | Deterministic prevention | 20-80 lines (JS) | 100% enforcement, no exceptions |
Agentic Architecture Patterns
The Agentic Loop
send → check stop_reason → execute tools → append → repeat
stop_reason == "end_turn"is the ONLY termination signal- Never parse text for "I'm done" (natural language termination)
- Never use arbitrary iteration caps (trust the model's signal)
- Claude returns text AND tool_use in the same response — check stop_reason, not content type
Multi-Agent Memory Isolation
Subagents do NOT share memory with coordinator or each other. All context must be passed explicitly via structured metadata (source URLs, doc names, page numbers).
Attention Dilution
14+ items in single pass → inconsistent depth. Fix: per-item analysis pass, then cross-item synthesis pass.
Session Management
| Strategy | When | Mechanism |
|---|---|---|
| Resume | Same task, no external changes | --resume |
| Fork | Explore alternative approach | Parallel worktrees |
| Fresh + Summary | Stale context, switching focus | New session + /wrapup notes |
What ships with it
6 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.
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.
- 3d ago First seen · 142 lines · 34 tokens per session scan A 3f6d3f4ec770
claude-code-patterns is a skill published in the GitHub repository terrene-foundation/metis (2 stars, last pushed 4mo ago), licensed Apache-2.0. It adds 34 tokens to every session and 1,297 once invoked, about $0.0002 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 2026-09-03.
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