---
title: "List a harness's native built-in tools"
method: GET
path: "/harness/{harnessId}/builtin-tools"
tags: ["Harness"]
---

# List a harness's native built-in tools

`GET /harness/{harnessId}/builtin-tools`

The native tools an agent harness (e.g. `claude-code`) runs INSIDE its sandbox — Bash, Read, Edit, Glob, Grep, WebSearch, and the like. Display-only: these execute via the harness's own agent loop and are NOT callable through MCPJam. Static published-package metadata; no project scope.

## Path parameters

- `harnessId` 'claude-code', required

## Response `200`

The harness's built-in tools.

- object
  - `items` object[], required
    - `key` string, required
    - `name` string, required
    - `commonName` string
    - `toolUseKind` string
    - `description` string
    - `inputSchema` object

## Other responses

- `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.
- `404` — Unknown project, server, or resource.
- `429` — Per-key rate limit exceeded (60 requests/minute sustained, bursts up to 10). Honor `Retry-After` and back off with jitter.
- `500` — Something failed on MCPJam's side.

## Changes

- **2026-07-25** `8e393fd5825f` — 4 warning
  - added the new `CONFLICT` enum value to the `code` response property for the response status `401`
  - added the new `CONFLICT` enum value to the `code` response property for the response status `404`
  - added the new `CONFLICT` enum value to the `code` response property for the response status `429`
  - added the new `CONFLICT` enum value to the `code` response property for the response status `500`
- **2026-06-28** `987c12430dc9` — 1 info
  - endpoint added

[Change history](https://skmtc.dev/mcpjam/apis/mcpjam-api/changes/harness/:harnessId/builtin-tools/get.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-service-production.skmtc.workers.dev/v1/apis/mcpjam/mcpjam-api/revisions/4c393eb80034/schema)