# Graph validate

`graph-validate` · version 1.0.0 · Graphs & scheduling · free, no key needed

Inspect a well-formed directed simple graph and report counts, isolated nodes, and maximum degrees.

**Use when you need to: graph validate · inspect directed graph structure · count isolated nodes and degrees.**

## Supported

- graph validate
- inspect directed graph structure
- count isolated nodes and degrees

## Not supported

- undirected mode
- weighted edges
- drawing
- files

## Behavior

- Input is a directed simple graph {nodes, edges} parsed with the shared graph grammar.
- Output is a null-prototype object with node_count, edge_count, self_loop_count, isolated_node_count, max_in_degree, and max_out_degree as integers.
- A self-loop counts once toward both in-degree and out-degree of its node.
- A node is isolated when its in-degree is 0 and its out-degree is 0.
- The empty graph yields 0 for every count, including max degrees.
- Self-loops and cycles are data; they are not rejected.

## Input

- `nodes` (array of string, required): max items 2000; each min length 1; each max length 256
- `edges` (array of object, required): max items 10000

## Output

- `node_count` (integer, required): min 0
- `edge_count` (integer, required): min 0
- `self_loop_count` (integer, required): min 0
- `isolated_node_count` (integer, required): min 0
- `max_in_degree` (integer, required): min 0
- `max_out_degree` (integer, required): min 0

## Limits

- max nodes: 2000
- max edges: 10000
- max node id bytes: 256

## Example

Request input:

```json
{
  "nodes": [
    "a",
    "b",
    "c",
    "d"
  ],
  "edges": [
    {
      "from": "a",
      "to": "b"
    },
    {
      "from": "a",
      "to": "c"
    },
    {
      "from": "c",
      "to": "c"
    }
  ]
}
```

Response:

```json
{
  "result": {
    "node_count": 4,
    "edge_count": 3,
    "self_loop_count": 1,
    "isolated_node_count": 1,
    "max_in_degree": 2,
    "max_out_degree": 2
  }
}
```

## How to call it

### MCP

Connect `https://computefirst.net/mcp` ([setup](/docs#connect)), then call `execute` with:

```json
{
  "id": "graph-validate",
  "version": "1.0.0",
  "input": {
    "nodes": [
      "a",
      "b",
      "c",
      "d"
    ],
    "edges": [
      {
        "from": "a",
        "to": "b"
      },
      {
        "from": "a",
        "to": "c"
      },
      {
        "from": "c",
        "to": "c"
      }
    ]
  }
}
```

### HTTP (no key)

```sh
curl -X POST https://computefirst.net/v1/tools/graph-validate/versions/1.0.0/execute \
  -H "Content-Type: application/json" \
  -d '{"nodes":["a","b","c","d"],"edges":[{"from":"a","to":"b"},{"from":"a","to":"c"},{"from":"c","to":"c"}]}'
```

The machine-readable contract is at [/v1/tools/graph-validate/versions/1.0.0](/v1/tools/graph-validate/versions/1.0.0).

### CLI

```sh
node cli.mjs run graph-validate 1.0.0 --input input.json --base-url https://computefirst.net
```

Get the client at [/clients/cli/](/clients/cli/).

## Related tools

- [Graph reachable from](/tools/graph-reachable-from): List nodes reachable from given sources by directed BFS, in discovery order.
- [Graph shortest unweighted path](/tools/graph-shortest-unweighted-path): Find a shortest directed path by fewest edges from source to target.
- [Graph ancestors](/tools/graph-ancestors): List every ancestor of given targets, including the targets, in reverse-graph BFS discovery order.
- [Graph dependency impact](/tools/graph-dependency-impact): List nodes downstream of a removed set: not themselves removed, reachable by a directed path of length at least 1.
- [Graph find cycle](/tools/graph-find-cycle): Find one directed cycle by 3-color DFS, or report that the graph is acyclic.
- [Graph induced subgraph](/tools/graph-induced-subgraph): Return the vertex-induced subgraph on a listed node subset, preserving declared node and edge order.