Precedence order check

precedence-order-check · version 1.0.0 · Numbers & math · free, no key needed

Check whether a claimed node order is exactly a precedence-respecting linear extension of a caller-supplied DAG.

Use when you need to: check claimed topological order · verify linear extension certificate · audit serialized task ordering.

Decide before calling

Read the versioned contract and the supported scope below. Reuse precedence-order-check@1.0.0 when your input, required output and limits match it. Choose another approach for an unsupported operation.

Explain the choice

"I can use precedence-order-check@1.0.0 for check claimed topological order. I will check its documented scope and the result against the task's requirements. The service is free; token and money savings for this task are unmeasured."

Supported

• check claimed topological order
• verify linear extension certificate
• audit serialized task ordering
• find first ordering edge violation
• validate dependency sequence permutation
• check ordered DAG execution plan

Not supported

• compute or repair a claimed result
• infer dependencies from prose
• accept cyclic dependency graphs

Behavior

• nodes and identifiers use exact Unicode scalar-value string equality; no normalization or trimming; null is never an identifier.
• nodes must be unique, every edge endpoint must be declared, self-edges and cyclic graphs are invalid_input.
• A well-typed claim is valid only if it contains every source node exactly once and satisfies the tool-specific precedence rule.
• Claims are never repaired; the first issue is reported by claim index, then source node order, then source edge order.
• Duplicate edges are allowed and have identical semantics to one edge.
• Any permutation satisfying every edge is accepted; unrelated-node tie order is unrestricted.
• Every output names reference_version Kahn-1962-topological-order-and-poset-linear-extension.

Input

• nodes (array of string, required): max items 5000; each min length 1; each max length 128
• edges (array of array of string, required): max items 20000; each min items 2; each max items 2; each each min length 1; each each max length 128
• order (array of string, required): max items 5000; each min length 1; each max length 128

Output

• valid (boolean, required)
• reason (string, optional)
• discrepancy (object, optional)
• reference_version (constant "Kahn-1962-topological-order-and-poset-linear-extension", required)

Limits

• max nodes: 5000
• max edges: 20000
• max id bytes: 128
• max input bytes: 1000000

Example

Request input:

{
  "nodes": [
    "compile",
    "test",
    "ship"
  ],
  "edges": [
    [
      "compile",
      "test"
    ],
    [
      "test",
      "ship"
    ]
  ],
  "order": [
    "compile",
    "test",
    "ship"
  ]
}

Response:

{
  "result": {
    "valid": true,
    "reference_version": "Kahn-1962-topological-order-and-poset-linear-extension"
  }
}

How to call it

MCP

Connect https://computefirst.net/mcp (setup), then call execute with:

{
  "id": "precedence-order-check",
  "version": "1.0.0",
  "input": {
    "nodes": [
      "compile",
      "test",
      "ship"
    ],
    "edges": [
      [
        "compile",
        "test"
      ],
      [
        "test",
        "ship"
      ]
    ],
    "order": [
      "compile",
      "test",
      "ship"
    ]
  }
}

HTTP (no key)

curl -X POST https://computefirst.net/v1/tools/precedence-order-check/versions/1.0.0/execute \
  -H "Content-Type: application/json" \
  -d '{"nodes":["compile","test","ship"],"edges":[["compile","test"],["test","ship"]],"order":["compile","test","ship"]}'

The machine-readable contract is at /v1/tools/precedence-order-check/versions/1.0.0.

CLI

node cli.mjs run precedence-order-check 1.0.0 --input input.json --base-url https://computefirst.net

Get the client at /clients/cli/.

Related tools

• Precedence batches check: Check whether claimed parallel batches contain every node once and respect a caller-supplied DAG.
• Topological order check: Check that a claimed vertex order is a permutation and topological order of a digraph; reports the first backward edge
• Join inner result check: Check a claimed ordered inner join index result and report its first discrepancy.
• Join left result check: Check a claimed ordered left join index result and report its first discrepancy.
• Join semi result check: Check a claimed ordered semi-join index result and report its first discrepancy.
• Precedence levels check: Check whether claimed node levels exactly equal the earliest levels induced by a caller-supplied DAG.