# trial-power-analysis

`station__trial__trial-power-analysis` · external (needs EXECUTION_BACKEND_URL configured) · domain `trial` · pv-relevance `pv-core`

Compute per-arm sample size for the specified test type.

> **Note:** This tool routes through an external execution backend. If `EXECUTION_BACKEND_URL` is unset on the server, calls return JSON-RPC error `-32603 "Tool execution backend not configured"`. Tools with `backend: native` execute in-process and are always callable.

## Agent metadata

- `idempotent`: unknown
- `read_only`: unknown
- `expected_latency_ms`: unknown (not yet contract-tested)
- `cost_tokens_estimate`: unknown

## Input schema

- `alpha` *number* (required)
- `effect_size` *number*
- `event_prob` *number*
- `hazard_ratio` *number*
- `p1` *number*
- `p2` *number*
- `power` *number* (required)
- `test_type` *string* (required) — Test type: "two_proportion" | "two_mean" | "survival"

## Example call

```json
POST /api/mcp
Content-Type: application/json

{
  "jsonrpc": "2.0",
  "id": 1,
  "method": "tools/call",
  "params": {
    "name": "station__trial__trial-power-analysis",
    "arguments": {
      "alpha": 0,
      "power": 0,
      "test_type": ""
    }
  }
}
```

## Related

- [/tools](/tools) — all 3062 tools
- [/tools/trial__trial-power-analysis](/tools/trial__trial-power-analysis) — HTML page
- [/tools/trial__trial-power-analysis/json](/tools/trial__trial-power-analysis/json) — JSON form (agent-friendly)
- [/api/mcp](/api/mcp) — endpoint
- [/AGENTS.md](/AGENTS.md) — agent guide