---
title: "Preview draft judge grading on one recorded iteration"
method: POST
path: "/projects/{projectId}/eval-runs/{runId}/judge/backtest"
tags: ["Eval runs"]
---

# Preview draft judge grading on one recorded iteration

`POST /projects/{projectId}/eval-runs/{runId}/judge/backtest`

Uses model budget and complete recorded evidence without changing the run verdict. Supply rubric.instructions, optional structured criteria, or null for objective-only grading. Continue with the unchanged rubric and returned cursor, sourceHash and reservationId. Completed page retries return cached results. Error cases have a null draft measurement.

## Path parameters

- `projectId` string, required
- `runId` string, required

## Headers

- `x-mcpjam-eval-vocabulary` '1' | '2'

## Request body

- object
  - `rubric` object, nullable, required
    - `instructions` string
    - `criteria` object[]
      - `id` string, required
      - `label` string, required
      - `description` string
      - `required` boolean
  - `continuation` object
    - `cursor` integer, required
    - `sourceHash` string, required
    - `reservationId` string, required

## Response `200`

One cached or newly graded page. Errors are unscored; isDone indicates the end of the population.

- object
  - `ok` boolean
  - `cases` object[]
  - `cursor` integer
  - `sourceHash` string
  - `reservationId` string
  - `isDone` boolean

## Other responses

- `400` — Malformed body or parameters.
- `401` — Missing, invalid, revoked, or orphaned key (`UNAUTHORIZED`) — or the **target MCP server** needs an OAuth grant (`OAUTH_REQUIRED`), which is a property of the server, not your key.
- `403` — Key is valid but not allowed to do this.
- `404` — Unknown project, server, or resource.
- `409` — Run is not terminal or source evidence changed.
- `429` — Per-key rate limit exceeded (60 requests/minute sustained, bursts up to 10). Honor `Retry-After` and back off with jitter.
- `504` — Backtest deadline or cancellation.

## Changes

- **2026-09-16** `ae334d76415e` — 1 info
  - endpoint added

[Change history](https://skmtc.dev/mcpjam/apis/mcpjam-api/changes/projects/:projectId/eval-runs/:runId/judge/backtest/post.md)

---

[API](https://skmtc.dev/mcpjam/apis/mcpjam-api.md) · [All operations](https://skmtc.dev/mcpjam/apis/mcpjam-api/llms.txt) · [OpenAPI document](https://skmtc.dev/mcpjam/apis/mcpjam-api/revisions/561e4fd0dfa2?raw)