# compute-time-to-onset

`station__calculate__compute-time-to-onset` · external (needs EXECUTION_BACKEND_URL configured) · domain `calculate` · pv-relevance `non-pv`

Analyze time-to-onset patterns using Weibull distribution. Shape parameter k indicates: k<1 early hazard (direct pharmacological), k≈1 constant hazard (idiosyncratic), k>1 late hazard (accumulation/sensitization).

> **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

- `onset_days` *array* (required) — Array of onset times in days after drug exposure (at least 3 positive values)

## Example call

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

{
  "jsonrpc": "2.0",
  "id": 1,
  "method": "tools/call",
  "params": {
    "name": "station__calculate__compute-time-to-onset",
    "arguments": {
      "onset_days": []
    }
  }
}
```

## Related

- [/tools](/tools) — all 3062 tools
- [/tools/calculate__compute-time-to-onset](/tools/calculate__compute-time-to-onset) — HTML page
- [/tools/calculate__compute-time-to-onset/json](/tools/calculate__compute-time-to-onset/json) — JSON form (agent-friendly)
- [/api/mcp](/api/mcp) — endpoint
- [/AGENTS.md](/AGENTS.md) — agent guide