# Filter result check

`filter-result-check` · version 1.0.0 · Numbers & math · free, no key needed

Checks an exact claimed decimal filter result with source-order witnesses.

**Use when you need to: check filter result · validate filtered selection · audit source order filter.**

## Decide before calling

Read the [versioned contract](/v1/tools/filter-result-check/versions/1.0.0) and the supported scope below. Reuse `filter-result-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 `filter-result-check@1.0.0` for check filter result. 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 filter result
- validate filtered selection
- audit source order filter
- check filter witnesses
- compare claimed filter output
- verify exact predicate selection

## Not supported

- does not return a repaired result
- does not evaluate JavaScript callbacks

## Behavior

- If the complete first-discrepancy verdict would exceed 4,096 UTF-8 JSON bytes, the tool throws limit_exceeded instead of truncating, omitting, or repairing either witness.
- Exact decimal strings are compared without binary floating point; numeric equality ignores trailing fractional zeroes.
- Filter witnesses must contain every matching source item exactly once in ascending source index; null fails ordered comparisons.

## Input

- `source` (array of string or null, required): max items 10000
- `predicate` (object, required)
- `claimed` (array of object, required): max items 10000

## Output

- `valid` (boolean, required)
- `reason` (string, optional)
- `discrepancy` (object, optional)
- `reference_version` (string, required)

## Limits

- max items: 10000
- max input bytes: 1000000
- max output bytes: 4096

## Example

Request input:

```json
{
  "source": [
    "2",
    "1",
    "2.0"
  ],
  "predicate": {
    "op": "gte",
    "value": "2"
  },
  "claimed": [
    {
      "source_index": 0,
      "value": "2"
    },
    {
      "source_index": 2,
      "value": "2.0"
    }
  ]
}
```

Response:

```json
{
  "result": {
    "valid": true,
    "reference_version": "ECMA-262-2026-Array-iteration-order+Hoare-1961-selection-invariants"
  }
}
```

## How to call it

### MCP

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

```json
{
  "id": "filter-result-check",
  "version": "1.0.0",
  "input": {
    "source": [
      "2",
      "1",
      "2.0"
    ],
    "predicate": {
      "op": "gte",
      "value": "2"
    },
    "claimed": [
      {
        "source_index": 0,
        "value": "2"
      },
      {
        "source_index": 2,
        "value": "2.0"
      }
    ]
  }
}
```

### HTTP (no key)

```sh
curl -X POST https://computefirst.net/v1/tools/filter-result-check/versions/1.0.0/execute \
  -H "Content-Type: application/json" \
  -d '{"source":["2","1","2.0"],"predicate":{"op":"gte","value":"2"},"claimed":[{"source_index":0,"value":"2"},{"source_index":2,"value":"2.0"}]}'
```

The machine-readable contract is at [/v1/tools/filter-result-check/versions/1.0.0](/v1/tools/filter-result-check/versions/1.0.0).

### CLI

```sh
node cli.mjs run filter-result-check 1.0.0 --input input.json --base-url https://computefirst.net
```

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

## Related tools

- [Join inner result check](/tools/join-inner-result-check): Check a claimed ordered inner join index result and report its first discrepancy.
- [Join left result check](/tools/join-left-result-check): Check a claimed ordered left join index result and report its first discrepancy.
- [Join semi result check](/tools/join-semi-result-check): Check a claimed ordered semi-join index result and report its first discrepancy.
- [Stable sort result check](/tools/stable-sort-result-check): Check that a claimed record result is the exact ascending stable sort of the supplied source records.
- [Partition result check](/tools/partition-result-check): Checks both sides of a claimed stable decimal partition with source witnesses.
- [Coloring count check](/tools/coloring-count-check): Check a proper indexed coloring and an exact canonical-decimal claim for its number of distinct colors.