# encode

`station__stoichiometry__encode` · external (needs EXECUTION_BACKEND_URL configured) · domain `stoichiometry` · pv-relevance `pv-adjacent`

Encode a concept and its definition as a balanced primitive equation. Returns the equation, balance status, and display form.

> **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

- `concept` *string* (required) — The concept name to encode (e.g., 'adverse_event', 'signal_detection')
- `definition` *string* (required) — Plain-text definition of the concept
- `source` *string* — Source (e.g., 'ICH E2A', 'CIOMS 1', 'FDA Guidance'). Default: custom

## Example call

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

{
  "jsonrpc": "2.0",
  "id": 1,
  "method": "tools/call",
  "params": {
    "name": "station__stoichiometry__encode",
    "arguments": {
      "concept": "",
      "definition": ""
    }
  }
}
```

## Related

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