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/epochal-dev/open-notebook-mcp/agents-mdgit clone --depth 1 https://github.com/Epochal-dev/open-notebook-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/epochal-dev/open-notebook-mcp/agents-md)<a href="https://agentmods.dev/instructions/epochal-dev/open-notebook-mcp/agents-md"><img src="https://agentmods.dev/badge/instructions/epochal-dev/open-notebook-mcp/agents-md.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 | $0.03133 | $0.03133 |
| Opus 5 | $0.01566 | $0.01566 |
| Sonnet 5 | $0.00627 | $0.00627 |
| Haiku 4.5 | $0.00313 | $0.00313 |
Grade A, and why
open-notebook-mcp AGENTS.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 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 — 446 lines — stays where its author put it; the contents beside it link to each section on GitHub.
AGENTS.md — MCP Server Best Practices (Python / FastMCP) — Codex-First
This file is the operating manual for an agent (Codex) that implements MCP servers in Python. Goal: MCP servers that are discoverable on-demand, context-efficient, predictable, testable, and deployable over STDIO and Streamable HTTP.
Core idea: avoid stuffing every tool definition + every intermediate result into the model context. Prefer progressive disclosure and compute/filter in the execution environment, returning compact results.
1) Prime directive: context efficiency > everything
- Default to small outputs. If it might be big, return a summary + handle (cursor/id/path).
- Filter/transform server-side. Don’t stream 10,000 rows into the model just to filter them.
- Progressive disclosure is mandatory. Every server must implement
search_capabilities(...)with adetaillevel. - Prefer composable tools. Many small orthogonal tools beat one mega-tool.
- Deterministic behavior. Stable error codes, stable schemas, stable names.
2) Hard requirement: standardized progressive disclosure
You are standardizing a discovery pattern across all MCP servers:
2.1 Required tool: search_capabilities
Contract
- Inputs:
query: str(free text)detail: Literal["name","summary","full"] = "summary"limit: int = 20(server-enforced max, e.g. 50)
- Output (JSON object):
matches: list[CapabilityMatch]count: inthint: str | None(optional “try these queries/tags”)
Detail levels
name: tool names onlysummary: name + one-liner + tagsfull: summary + parameters + return shape + 1 example call + typical output size
Why
- Lets Codex find just what it needs without loading every tool definition.
- Lets you keep tool descriptions minimal and stable.
2.2 Optional but strong: manifest resource
Expose a small read-only “server manifest” resource for metadata (name/version/base_url/tags).
Use it for humans and debugging, not as a substitute for search_capabilities.
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 · 446 lines · 3,133 tokens per session scan A e8b87d134b82
open-notebook-mcp AGENTS.md is an instructions file published in the GitHub repository Epochal-dev/open-notebook-mcp (43 stars, last pushed 8mo ago), licensed MIT. It adds 3,133 tokens to every session, about $0.0157 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.
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).
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next.js AGENTS.md
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