# viz-gpu-layout

`station__observatory__viz-gpu-layout` · external (needs EXECUTION_BACKEND_URL configured) · domain `observatory` · pv-relevance `non-pv`

Run force-directed graph layout (CPU-side Fruchterman-Reingold / ForceAtlas2).

> **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

- `edges` *array* (required) — Edge list as [source, target, source, target, ...] (0-indexed)
- `height` *number* (required)
- `iterations` *integer* (required)
- `node_count` *integer* (required) — Number of nodes
- `weights` *array*
- `width` *number* (required)

## Example call

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

{
  "jsonrpc": "2.0",
  "id": 1,
  "method": "tools/call",
  "params": {
    "name": "station__observatory__viz-gpu-layout",
    "arguments": {
      "edges": [],
      "height": 0,
      "iterations": 0,
      "node_count": 0,
      "width": 0
    }
  }
}
```

## Related

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