Borrowing it
Nothing to install: this file belongs to jurek-f/prompt-lab-mcp. 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/jurek-f/prompt-lab-mcp/main/CLAUDE.mdgit clone --depth 1 https://github.com/jurek-f/prompt-lab-mcpWrote 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/jurek-f/prompt-lab-mcp/claude-md)<a href="https://agentmods.dev/instructions/jurek-f/prompt-lab-mcp/claude-md"><img src="https://agentmods.dev/badge/instructions/jurek-f/prompt-lab-mcp/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/jurek-f/prompt-lab-mcp/claude-md"><img src="https://agentmods.dev/badge/instructions/jurek-f/prompt-lab-mcp/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 | $0.03552 | $0.03552 |
| Opus 5.5 | $0.01421 | $0.01421 |
| Sonnet 5.5 | $0.00710 | $0.00710 |
| Haiku 4.5 | $0.00355 | $0.00355 |
Grade A, and why
prompt-lab-mcp 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 — 332 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Agent instructions
What this server is
overhang-mcp is a lightweight broker that connects the Prompt Lab web UI to a Claude Code agent running prompt optimisation loops. It holds workspace state (system prompt, test cases, results, suggestions) and exposes it via HTTP (to the UI) and MCP (to the agent).
No LLM calls happen here. The agent (you) owns all LLM work.
Session startup — do this first
MANDATORY. Do not skip. Do not defer. Do not wait to be reminded.
Step 1 — Scan for templates (ALWAYS, no exceptions)
Run these two commands immediately at the start of every session:
ls prompt-lab/templates/
ls prompt-lab/system-prompts/
Even if you think there are no templates, run the commands. Even if you were just connected and think you already know the state, run the commands.
Step 2 — If files exist, ALWAYS ask before pushing to the UI
If you find any .json files in prompt-lab/templates/ or .txt files in prompt-lab/system-prompts/, STOP and ask the user:
"I found N test suite template(s): [list names] and M system prompt template(s): [list names]. Should I push all of them to the UI?"
Do NOT push anything without asking first. Pushing takes time — wait for confirmation.
Step 3 — If user says yes, push ALL of them to the UI
Push every file — not just the one the user wants to work with. All of them.
Test suite templates — for every .json file:
save_template(name=<file.name field or filename without extension>, testCases=<file.testCases>)
System prompt templates — for every .txt file:
save_system_prompt_template(name=<filename without extension>, content=<file contents>)
Call save_template / save_system_prompt_template once per file. All pushed templates appear in the UI dropdowns. The question of which one to work with comes after pushing, not instead of it.
After pushing, confirm: "Pushed N test suite(s) and M system prompt template(s) to the UI — all visible in the dropdowns."
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 · 332 lines · 3,552 tokens per session scan A 522861501bac
prompt-lab-mcp CLAUDE.md is an instructions file published in the GitHub repository jurek-f/prompt-lab-mcp (0 stars, last pushed 4mo ago), licensed MIT. It adds 3,552 tokens to every session, about $0.0142 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.
prompt-lab-mcp CLAUDE.md compared with instructions from other repositories
| Mod | Type | Stars | Last push | Licence | Scan | Tokens | Works with |
|---|---|---|---|---|---|---|---|
| prompt-lab-mcp CLAUDE.mdjurek-f/prompt-lab-mcp | Instructions file | 0 | 4mo ago | MIT | A | 3,552 | Claude Code |
| vscode buildNext.instructions.mdmicrosoft/vscode | Instructions file | 195k | yesterday | MIT | A | 9,719 | GitHub Copilot |
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| 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 |