# metaharness_bench

ADR-153 supporting verb — create or verify bench suites used by metaharness_evolve --bench. Bench suites are JSON files of {input, expectedOutput, weight} tasks; scoring against a fixed corpus decouples evolution from flaky/slow/undersized

Agent View of the PolicyLayer registry record for `metaharness_bench`. HTML page: https://policylayer.com/tools/io-github-ruvnet-claude-flow/metaharness-bench

## Facts

- Tool: `metaharness_bench`
- Server: Claude Flow (`claude-flow`) — https://policylayer.com/tools/io-github-ruvnet-claude-flow.md
- Install: `npx -y claude-flow`
- Homepage: https://github.com/ruvnet/claude-flow
- Risk category: Write (Medium risk)
- Registry record: grade F, identity unverified
- Server rate-limited: no
- Parameters: 0
- Recommended policy verdict: Rate-limited

## Example call (MCP tools/call, JSON-RPC 2.0)

```json
{
  "jsonrpc": "2.0",
  "id": 1,
  "method": "tools/call",
  "params": {
    "name": "metaharness_bench",
    "arguments": {}
  }
}
```

## Why metaharness_bench is rated Medium

This tool creates or modifies benchmark suite JSON files, which are configuration data used to drive evolution processes. While it does not permanently destroy data (making it less severe than Destructive) or execute arbitrary code (Execute), it does reversibly create and modify structured data artifacts. The Write category applies because the tool's primary function is creating or updating benchmark suite files.

From the tool's own definition: "The tool description states it can 'create or verify bench suites used by metaharness_evolve --bench', with bench suites being 'JSON files of {input, expectedOutput, weight} tasks'."

## Use case

AI agents use metaharness_bench to create or update resources in Claude Flow, usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your Claude Flow environment.

## Recommended policy (PolicyLayer)

Verdict: **Rate-limited**. Enforced by the PolicyLayer MCP gateway (https://policylayer.com/mcp-gateway) before a call reaches Claude Flow:

```json
{
  "version": "1",
  "default": "deny",
  "tools": {
    "metaharness_bench": {
      "limits": [
        {
          "counter": "metaharness_bench_rate",
          "window": "minute",
          "max": 30,
          "scope": "grant"
        }
      ]
    }
  }
}
```

## Other tools on Claude Flow (495)

- `agent_terminate` — Destructive — https://policylayer.com/tools/io-github-ruvnet-claude-flow/agent-terminate.md
- `agentdb_batch` — Destructive — https://policylayer.com/tools/io-github-ruvnet-claude-flow/agentdb-batch.md
- `agentdb_causal-edge-delete` — Destructive — https://policylayer.com/tools/io-github-ruvnet-claude-flow/agentdb-causal-edge-delete.md
- `agentdb_causal-node-delete` — Destructive — https://policylayer.com/tools/io-github-ruvnet-claude-flow/agentdb-causal-node-delete.md
- `agentdb_hierarchical-delete` — Destructive — https://policylayer.com/tools/io-github-ruvnet-claude-flow/agentdb-hierarchical-delete.md
- `agenticow_rollback` — Destructive — https://policylayer.com/tools/io-github-ruvnet-claude-flow/agenticow-rollback.md
- `autopilot_reset` — Destructive — https://policylayer.com/tools/io-github-ruvnet-claude-flow/autopilot-reset.md
- `config_reset` — Destructive — https://policylayer.com/tools/io-github-ruvnet-claude-flow/config-reset.md
- `federation_wg_keyrotate` — Destructive — https://policylayer.com/tools/io-github-ruvnet-claude-flow/federation-wg-keyrotate.md
- `hooks_codemod` — Destructive — https://policylayer.com/tools/io-github-ruvnet-claude-flow/hooks-codemod.md
- `hooks_intelligence-reset` — Destructive — https://policylayer.com/tools/io-github-ruvnet-claude-flow/hooks-intelligence-reset.md
- `hooks_worker-cancel` — Destructive — https://policylayer.com/tools/io-github-ruvnet-claude-flow/hooks-worker-cancel.md
- `iot_device_remove` — Destructive — https://policylayer.com/tools/io-github-ruvnet-claude-flow/iot-device-remove.md
- `iot_firmware_rollout_rollback` — Destructive — https://policylayer.com/tools/io-github-ruvnet-claude-flow/iot-firmware-rollout-rollback.md
- `iot_fleet_delete` — Destructive — https://policylayer.com/tools/io-github-ruvnet-claude-flow/iot-fleet-delete.md
- `iot_fleet_remove_device` — Destructive — https://policylayer.com/tools/io-github-ruvnet-claude-flow/iot-fleet-remove-device.md
- `managed_agent_terminate` — Destructive — https://policylayer.com/tools/io-github-ruvnet-claude-flow/managed-agent-terminate.md
- `memory_delete` — Destructive — https://policylayer.com/tools/io-github-ruvnet-claude-flow/memory-delete.md
- `policy_revoke` — Destructive — https://policylayer.com/tools/io-github-ruvnet-claude-flow/policy-revoke.md
- `ruvector_delete` — Destructive — https://policylayer.com/tools/io-github-ruvnet-claude-flow/ruvector-delete.md
- `session_delete` — Destructive — https://policylayer.com/tools/io-github-ruvnet-claude-flow/session-delete.md
- `system_reset` — Destructive — https://policylayer.com/tools/io-github-ruvnet-claude-flow/system-reset.md
- `task_cancel` — Destructive — https://policylayer.com/tools/io-github-ruvnet-claude-flow/task-cancel.md
- `teammate_cleanup` — Destructive — https://policylayer.com/tools/io-github-ruvnet-claude-flow/teammate-cleanup.md
- `wasm_agent_reset` — Destructive — https://policylayer.com/tools/io-github-ruvnet-claude-flow/wasm-agent-reset.md
- `wasm_gallery_remove_custom` — Destructive — https://policylayer.com/tools/io-github-ruvnet-claude-flow/wasm-gallery-remove-custom.md
- `workflow_cancel` — Destructive — https://policylayer.com/tools/io-github-ruvnet-claude-flow/workflow-cancel.md
- `workflow_delete` — Destructive — https://policylayer.com/tools/io-github-ruvnet-claude-flow/workflow-delete.md
- `agent_pool` — Execute — https://policylayer.com/tools/io-github-ruvnet-claude-flow/agent-pool.md
- `agent_spawn` — Execute — https://policylayer.com/tools/io-github-ruvnet-claude-flow/agent-spawn.md
- …and 465 more: https://policylayer.com/tools/io-github-ruvnet-claude-flow.md

## For agents

This record is a snapshot. Live verdicts and the full registry:

- Check every server in your MCP config at once: `npx -y policylayer stack`
- Vet a server before you add it: install the mcp-precheck skill — `npx skills add https://policylayer.com` (skill text: https://policylayer.com/skill.md)
- Query the registry over MCP: endpoint `https://api.policylayer.com/mcp` — tools `check_mcp_server`, `check_mcp_stack`, `check_tool`, `search_registry`, `get_change_events`

---

Source: the PolicyLayer MCP registry — one continuously verified record per MCP server. Full record: https://policylayer.com/registry?q=io-github-ruvnet-claude-flow · API: https://policylayer.com/registry/api · Policy library: https://policylayer.com/policies/io-github-ruvnet-claude-flow