# Formats & limits

> Supported file types, output formats, size caps, expiry windows, and quotas across both surfaces.

## Source documents

| Format | Compare | Merge / combine / version history |
| --- | --- | --- |
| `.docx` | Yes | Yes |
| `.doc` | Yes | Yes |
| `.pdf` | Yes | Yes |

Anything that is not already `.docx` is converted server-side before comparison, so `.doc`
and `.pdf` sources spend noticeably longer in `processing` than `.docx` ones.

## Output formats

Over REST, pass the renderings you want as the `format` query parameter. It is repeatable
and also accepts a comma-separated list, so `?format=docx&format=md` and `?format=docx,md`
both ask for two:

| `format` | Compare | Merge |
| --- | --- | --- |
| `docx` | Word document with tracked changes — the default | The merged Word document — the default |
| `pdf` | PDF rendering of the redline | — |
| `pdf_changed_pages_only` | PDF of only the changed pages | — |
| `md` | Markdown rendering of the redline | Markdown rendering of the merged document |

Over MCP, pass them in `download_options`, or `["all"]` for every available format:

| Operation | `download_options` value | Produces |
| --- | --- | --- |
| Compare | `word_redline` | Word document with tracked changes |
| Compare | `pdf_redline` | PDF rendering of the redline — the default |
| Compare | `pdf_changed_pages_only` | PDF of only the changed pages |
| Merge | `merged_docx` | Merged Word document |
| Combine | `combined_docx` | Combined Word document |
| Version history | `version_history_docx` | Attributed Word document |

**Note the different defaults.** REST defaults to `docx`, the Word tracked-changes file.
MCP defaults to the comparison's previewable rendering, `pdf_redline`. Set the format
explicitly if it matters to you.

Renderings do not finish together — the PDF and the Markdown trail the Word document. A REST
response returns every requested format that is ready and names the rest in
`pending_formats`, and reports `status: "ready"` only once all of them exist. Asking for one
format gets you an answer sooner than asking for several.

## Size and rate limits

| Limit | Value |
| --- | --- |
| Maximum file size | 100 MB per file |
| Author label length | 100 characters; longer values are truncated |
| Revisions per merge | At least 2 |
| Server-side URL fetch (`create_comparison_from_links`) | 100 MB, 30-second timeout, at most 3 redirects |
| Concurrent MCP uploads | 16 server-wide; a saturated server returns `503` with `Retry-After: 1` |
| MCP upload request timeout | 300 seconds |
| MCP wait-tool budget | About 55 seconds per call, with keepalives every 5 seconds |
| REST suggested poll interval | 1 second, via `Retry-After` |

Files larger than 100 MB need the in-app upload flow rather than either API.

## Expiry

Every signed URL — upload authorizations, upload manifests, download manifests, per-file
download URLs, and `text_url` — is valid for **one hour** from issue.

This is rarely a real constraint. The wait tools and the REST status endpoint mint fresh
URLs on every call, so a finished artifact stays reachable indefinitely; only the link
itself ages out. If an upload manifest lapses before its transfers happen, call the create
tool again with the same `version_story_id` to stage fresh ones.

## Quotas

Organizations on a metered plan have a monthly document-upload allowance covering free
seats. When it is exhausted:

- **REST** returns `402` with code `USAGE_LIMIT_REACHED`. The check runs before anything is
  created, so a rejected request costs nothing.
- **MCP** raises a tool error whose message includes an upgrade link.

This is a billing state, not a transient failure — retrying will not clear it. Paid seats
are not subject to the upload allowance.