# evals-mcp-server MCP Server

Author verifiable eval records through a draft→review→revise→submit loop with enforced graders.

**Publisher claimed.** No tool list reported, and Pod has not connected to this server.

## Status

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## Connect

Published as `@cyanheads/evals-mcp-server` on npm. Runs locally.

## Known issues

**9 problems reported by people outside the maintainer team.** Issues filed by the project's own owners, members and collaborators are excluded — those are release checklists and internal refactors, not things that will go wrong for you. Showing 6.

### Most discussed

### test(evals_revise_draft): mcq_choice_mismatch path not covered

\`evals_revise_draft\` declares \`mcq_choice_mismatch\` in its typed error contract (alongside \`task_type_constraint\`), and the handler calls the shared \`assertTaskTypeConstraints\` after each patch — so patching \`grader.correct\` to a value not in \`choices[]\` should fire \`mcq_choice_mismatch\`. There is no test that exercises this path.

## Proposal

Add a test (or test case in \`tests/authoring-loop.test.ts\` or a new \`tests/tools/revise-draft.tool.test.ts\`) that:

1. Creates an mcq d

[Read the thread](https://github.com/cyanheads/evals-mcp-server/issues/4) · 2026-06-28 · closed · 2 comments

### ux(evals_get_record): description is meta-coaching — names the caller, not the action

The current `evals_get_record` description reads:

> "Read a draft or submitted eval record by id. The verification subagent calls this to inspect a draft before re-deriving or looking up the gold. The id is stable across submit, so it resolves a record whether it is still a draft or already submitted."

The second sentence names a specific caller type ("verification subagent") and workflow step ("before re-deriving or looking up the gold") — that is meta-coaching, not a description of what the 

[Read the thread](https://github.com/cyanheads/evals-mcp-server/issues/3) · 2026-06-25 · closed · 1 comment

### feat(config): default EVALS_DATA_DIR to ./evals-data so bare npx invocations work

`EVALS_DATA_DIR` is required with no default — omitting it aborts startup with a config error. `.env.example` already lists `./evals-data` as the natural value. A hardcoded default would let `npx`/bare invocations work without any env setup, lowering the barrier for first use.

## Proposal

Apply `./evals-data` as the fallback in `src/config/server-config.ts` when `EVALS_DATA_DIR` is unset. Keep the existing `.min(1)` guard — it rejects an empty string (`EVALS_DATA_DIR=`) with a clear validation

[Read the thread](https://github.com/cyanheads/evals-mcp-server/issues/2) · 2026-06-25 · closed · 1 comment

### bug(evals_create_draft): mcq grader correct-not-in-choices fires task_type_constraint instead of mcq_choice_mismatch

### Server version

0.1.0

### Runtime

Bun

### Transport

HTTP / stdio

### Description

`evals_create_draft` fires `reason: "task_type_constraint"` when the `mcq` grader's `correct` value is not in `choices[]`, but the error contract documents this case as `reason: "mcq_choice_mismatch"`. `evals_run_check` correctly returns `mcq_choice_mismatch` for the same condition — the two tools are inconsistent.

### Steps to reproduce

1. Call `evals_create_draft` with `task_type: "mcq"`, `choices: ["P

[Read the thread](https://github.com/cyanheads/evals-mcp-server/issues/1) · 2026-06-25 · closed · 1 comment

### bug(evals_revise_draft): unknown set path reports false success

### Server version

0.1.2

### mcp-ts-core version

0.12.3

### Runtime

Bun

### Runtime version

Bun 1.4.0

### Transport

HTTP (Streamable HTTP)

### Description

`evals_revise_draft` reports an unknown `set` path as successfully applied even though schema validation removes it from the stored record. The success response makes the mutation appear effective when it was a no-op.

### Steps to reproduce

1. Create a valid draft with `evals_create_draft`.
2. Call `evals_revise_draft` with `{ "dr

[Read the thread](https://github.com/cyanheads/evals-mcp-server/issues/9) · 2026-08-22 · open · 0 comments

### Most recent

### bug(grader): numeric grader accepts complex/unit candidates by truncating at the first space

### Server version

0.1.2

### mcp-ts-core version

0.10.9

### Runtime

Bun

### Runtime version

Bun 1.3.x (logic bug — runtime-agnostic)

### Transport

stdio

### Description

The `numeric` grader coerces a [math.js](https://mathjs.org/) result to a plain number with `Number(result.toString().replace(/\s.*$/, ''))` (`candidateToNumber` and `resolveNumber` in `src/services/grader/grader-service.ts`). For any non-real result — a math.js `Complex` or `Unit` — `toString()` yields e.g. `"2 + 3i"`

[Read the thread](https://github.com/cyanheads/evals-mcp-server/issues/5) · 2026-06-30 · open · 0 comments

[See all 9 reports Pod holds for evals-mcp-server](/mcp/evals-mcp-server/issues).

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