# Xpath10 count

`xpath10-count` · version 1.0.0 · Structured formats · free, no key needed

Count the nodes in an XPath 1.0 node-set from location paths, axes, predicates, namespaces and union.

**Use when you need to: count xpath 1.0 node set · how many xml nodes match this xpath · xpath count function for a location path.**

## Decide before calling

Read the [versioned contract](/v1/tools/xpath10-count/versions/1.0.0) and the supported scope below. Reuse `xpath10-count@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 `xpath10-count@1.0.0` for count xpath 1.0 node set. 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

- count xpath 1.0 node set
- how many xml nodes match this xpath
- xpath count function for a location path
- size of an xpath union node set
- number of nodes selected by xpath 1.0
- count elements attributes or namespaces by xpath

## Not supported

- returning the selected nodes or their paths
- calling count() inside the XPath expression
- XPath 2.0 sequence cardinality and arithmetic

## Behavior

- Returns the XPath 1.0 count() of the same node-set xpath10-select would return. The result is {count} and nothing else.
- Union duplicates are eliminated first, so //para | //para on two para elements counts 2.
- //para[1] counts the first para child of each parent. /descendant::para[1] counts one node. / counts the root, which is always 1.
- count(/r), arithmetic, variables and XPath 2.0 syntax are unsupported_input. The count is not computed by evaluating a count() call inside the expression.
- A missing match counts 0. Limits and malformed XML or XPath fail with the same codes as xpath10-select, before a count is returned.

## Input

- `xml` (string, required): min length 1; max length 4096
- `expression` (string, required): min length 1; max length 1024
- `namespaces` (object, optional)

## Output

- `count` (integer, required): min 0; max 400

## Limits

- max xml bytes: 4096
- max expression bytes: 1024
- max depth: 32
- max nodes: 400
- max steps: 100000
- max output bytes: 32768
- max namespace bindings: 16
- max namespace uri bytes: 512
- max name chars: 256
- max union operands: 32
- max xpath depth: 32

## Example

Request input:

```json
{
  "xml": "<doc><para>A</para><sec><para>B</para><para>C</para></sec></doc>",
  "expression": "//para[1]"
}
```

Response:

```json
{
  "result": {
    "count": 2
  }
}
```

## How to call it

### MCP

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

```json
{
  "id": "xpath10-count",
  "version": "1.0.0",
  "input": {
    "xml": "<doc><para>A</para><sec><para>B</para><para>C</para></sec></doc>",
    "expression": "//para[1]"
  }
}
```

### HTTP (no key)

```sh
curl -X POST https://computefirst.net/v1/tools/xpath10-count/versions/1.0.0/execute \
  -H "Content-Type: application/json" \
  -d '{"xml":"<doc><para>A</para><sec><para>B</para><para>C</para></sec></doc>","expression":"//para[1]"}'
```

The machine-readable contract is at [/v1/tools/xpath10-count/versions/1.0.0](/v1/tools/xpath10-count/versions/1.0.0).

### CLI

```sh
node cli.mjs run xpath10-count 1.0.0 --input input.json --base-url https://computefirst.net
```

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

## Related tools

- [Xpath10 select](/tools/xpath10-select): Select an XPath 1.0 node-set from location paths, axes, predicates, namespaces and union, in document order.
- [Xpath10 paths](/tools/xpath10-paths): List the canonical XPath 1.0 path of each node in a location-path node-set, in document order.
- [Xpath10 boolean](/tools/xpath10-boolean): Evaluate an XPath 1.0 boolean expression: comparisons, and, or, not, starts-with, contains, and boolean conversion.
- [Xpath10 evaluate](/tools/xpath10-evaluate): Evaluate an XPath 1.0 value expression and return its type with an exact string, number, or boolean token.
- [XML exc c14n subtree](/tools/xml-exc-c14n-subtree): Exclusive XML Canonicalization 1.0 of one selected element and its descendants.
- [Xpath10 number](/tools/xpath10-number): Evaluate an XPath 1.0 numeric expression: arithmetic, div, mod, floor, ceiling, round, and number conversion.