> ## Documentation Index
> Fetch the complete documentation index at: https://clickclack.mintlify.site/llms.txt
> Use this file to discover all available pages before exploring further.

# Check a receipt

> Verify a Click Clack signed history on your own machine. You do not need the app, an account, or a network connection for the ordinary check.

You were handed a JSON file — a Click Clack **signed history**. This page is how you check it without asking Click Clack to vouch for itself.

You need [Node.js 22](https://nodejs.org/) or newer. The checker never contacts Click Clack.

## Install the checker

The independent checker is Apache-2.0. It is a small program, not the writing studio.

```bash theme={null}
npm install --global @click-clack/provenance-verifier
```

That puts `click-clack-verify` on your `PATH`. Running it with no arguments prints usage and exits `2` — that is enough to confirm the command is installed.

## Run it

```bash theme={null}
click-clack-verify export.json
```

Replace `export.json` with the file you were given.

<Steps>
  <Step title="Read the exit status">
    `0` means the proof is valid. `1` means the proof failed. `2` means the file could not be read as a Click Clack export.
  </Step>

  <Step title="Read the JSON line">
    A valid run prints a summary object. `valid` is `true`. `operatorIndependentNonRepudiation` is always `false` — that field is not a score, it is a limit.
  </Step>

  <Step title="Match it to the manuscript">
    The export carries the draft it is about. `boundToManuscript` is `true` when the signed checkpoint is bound to that text. If the writer typed after the last signed contribution, `headDescribesManuscript` can be `false`. That is ordinary, not a failure.
  </Step>
</Steps>

## Compare with an earlier receipt

If you kept a previous export, you can ask whether this one continues that one without contradicting it:

```bash theme={null}
click-clack-verify current.json --expect-continues earlier.json
```

A valid continuation still has exit status `0`. The summary then includes `continuesEarlier`, how many events the earlier file had, and how many were appended since.

## Pin a workspace fingerprint

If you already know the workspace fingerprint from a receipt you accepted, refuse a file that does not match:

```bash theme={null}
click-clack-verify export.json --expect-workspace-fingerprint <64-lowercase-hex-characters>
```

## Machine-readable output

`--json` adds an explicit `capabilities` object describing what this checker version can prove. Use it when you are recording the result rather than reading it.

```bash theme={null}
click-clack-verify export.json --json
```

## Library use

```js theme={null}
import { verifyExport } from '@click-clack/provenance-verifier';

const result = verifyExport('export.json', {
    earlierExportFile: 'earlier.json',
});
```

The package ships fictional, deterministically signed fixtures. Tampered fixtures are expected to fail — they are how you confirm you are running a real checker.

<Warning>
  A page in Click Clack that says **Signed** is Click Clack reporting on its own signature. It is not the independent check. For that, run `click-clack-verify` on the downloaded file.
</Warning>

})