evals-mcp-server: Instructions file for Claude Code

CLAUDE.md

evals-mcp-server CLAUDE.md is an instructions file for Claude Code from cyanheads/evals-mcp-server. It costs 6,157 tokens per session, scanned A, a copy of obsidian-mcp-server AGENTS.md, Apache-2.0.

Instructions for developing evals-mcp-server, a server that helps an agent create and check evaluation records. An evaluation record is a structured test used to judge whether an agent's result is correct.

In plain words
What is it for?
Guiding work on the draft, review, revision, and submission loop, including schema handling, grading, normalization, persistence, and compilation.
Why use it?
They define the server's development rules, authoring workflow, tools, storage approach, and required framework documentation.

Instructions file for Claude Code

Written for Claude Code: Claude Code plugin machinery. Also seen: reads .claude/ paths; mentions CLAUDE.md; mentions subagents.

This is cyanheads/evals-mcp-server's own configuration. It tells Claude Code how to work on evals-mcp-server itself, so it is not a mod to install elsewhere. Copy it as a starting point and replace the rules that are about this project. Everything evals-mcp-server configures →

Reuse

Borrowing it

Nothing to install: this file belongs to cyanheads/evals-mcp-server. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.

Copy the file
curl -O https://raw.githubusercontent.com/cyanheads/evals-mcp-server/main/CLAUDE.md
Clone the repo
git clone --depth 1 https://github.com/cyanheads/evals-mcp-server

Made for: Claude Code.

Wrote 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.

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README.md
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<a href="https://agentmods.dev/instructions/cyanheads/evals-mcp-server/claude-md"><img src="https://agentmods.dev/badge/instructions/cyanheads/evals-mcp-server/claude-md.svg" alt="Measured on agentmods" height="20"></a>
Per session 6,157 This file is loaded in full into every session.
When invoked 6,157 The same file — it is already loaded in full.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.
Origin 80% copy Near-identical to another mod in the catalogue.
Token cost

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.

ModelPer sessionOnce invoked
Fable 5.1 $0.06157 $0.06157
Opus 5 $0.03078 $0.03078
Sonnet 5 $0.01231 $0.01231
Haiku 4.5 $0.00616 $0.00616

Measured 7d ago against content hash b6b97739e669, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-07, from the pricing page.

Security

Grade A, and why

evals-mcp-server 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 7d 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.

Origin

This is a copy

80% identical to obsidian-mcp-server AGENTS.md — 362 lines differ, which has more behind it and is treated as the original. This page carries a canonical link to it rather than competing with it.

CLAUDE.md · 419 lines

How it starts

The opening of the file, as written. The whole thing — 419 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Developer Protocol

Server: evals-mcp-server Version: 0.1.3 Framework: @cyanheads/mcp-ts-core ^0.12.3 Engines: Bun ≥1.3.0, Node ≥24.0.0 MCP SDK: @modelcontextprotocol/server ^2.0.0 Zod: ^4.4.3

Read the framework docs first: node_modules/@cyanheads/mcp-ts-core/CLAUDE.md contains the full API reference — builders, Context, error codes, exports, patterns. This file covers server-specific conventions only.


This Server

evals-mcp-server turns an agent into an eval author. It's an authoring-loop server (not a data-source wrapper): the agent produces a verifiable eval record through a draft → review → surgical-revise → submit loop, and the server acts as both scribe (normalize, persist, compile) and adversarial checker (run the record's own grader, reject what doesn't hold up). No external API — the server is the source of truth, backed by plain JSON files under EVALS_DATA_DIR. Full concept + as-built surface: docs/design.md, docs/idea.md, docs/authoring-loop-pattern.md.

Surface (9 tools, 1 resource):

Primitive Purpose
evals_describe_schema Required/optional fields + grader options for a task_type (static).
evals_create_draft Create a draft; reflect it back with a review protocol + subagent prompt.
evals_get_record Read a draft or submitted record by id.
evals_revise_draft Surgical set/append/unset patch to a draft by dotted path.
evals_discard_draft Delete a draft.
evals_run_check Run a grader against candidates, PASS/REJECT, decoupled from any record.
evals_submit_draft Committability gate → freeze.
evals_list_records Filter records by status/domain/task_type/tag (summary projection).
evals_export_records Compile submitted records to JSONL/CSV/Inspect/lm-eval under exports/.
eval://record/{id} Resource mirror of evals_get_record.

Read the full file on GitHub · 419 lines

Changes

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.

  1. 7d ago First seen · 419 lines · 6,157 tokens per session scan A b6b97739e669

Subscribe to this mod's changes

evals-mcp-server CLAUDE.md is an instructions file published in the GitHub repository cyanheads/evals-mcp-server (1 stars, last pushed 16d ago), licensed Apache-2.0. It adds 6,157 tokens to every session, about $0.0308 per session on Opus 5. A static security scan graded it A with 0 findings. It is 80% identical to obsidian-mcp-server AGENTS.md, differing in 362 lines, and is treated as a copy.

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