v5 makes the difference between adding new information and replacing the canonical source explicit.

### Choose the correct write

| Intent | Operation | Content behavior |
| --- | --- | --- |
| Add information to a stable caller ID | `POST /ns/{namespace}/document` | Append/diff |
| Replace text or URL content | `PATCH /ns/{namespace}/document/{id}` | Replace and reprocess |
| Update only supporting fields | Same `PATCH` without `content` | Canonical content unchanged |
| Replace a source file and its user metadata | `POST /ns/{namespace}/document/file/{id}` | Full replacement and reprocess |
| Partially update a file or its supporting fields | `PATCH /ns/{namespace}/document/file/{id}` | Omitted fields remain unchanged |

### Update text or URL content

<CodeGroup>
```bash Legacy
PATCH /v3/documents/doc_1
{"content":"corrected source","metadata":{"revision":2}}
```

```bash v5
PATCH /ns/user_1/document/doc_1?dreaming=dynamic
{"content":"corrected source","metadata":{"revision":2}}
```
</CodeGroup>

The v5 body accepts any non-empty subset of `content`, `supportingContext`, `metadata`, `group`, or `date`. Supplying `content` makes it the new canonical source; facts supported only by the previous source can disappear after reprocessing.

### Replace a file-backed document

```bash
POST /ns/user_1/document/file/doc_1?dreaming=dynamic
Content-Type: multipart/form-data

file=@corrected.pdf
metadata={"revision":2}
```

POST requires `file` and replaces the canonical source plus user-controlled metadata, grouping, context, and date. Omitted supporting fields are cleared. Use it when the submitted request is the complete new representation of the file-backed document.

### Partially update a file-backed document

```bash
PATCH /ns/user_1/document/file/doc_1?dreaming=dynamic
Content-Type: multipart/form-data

metadata={"reviewed":true}
```

PATCH changes only supplied fields. Include `file` to replace the source while retaining omitted supporting fields, or omit `file` for metadata-, group-, context-, or date-only changes. `metadata` and `group` are JSON-encoded strings; `supportingContext` and `date` are plain strings.

<Warning>
  There is no public v5 `PUT /ns/{namespace}/document/file/{id}` operation. Use POST for a complete replacement and PATCH for a partial update.
</Warning>

### IDs and scope

The path `id` may be the Supermemory document ID or your caller-defined ID. It is resolved only inside `{namespace}`; an ID from another namespace is not a cross-namespace update mechanism.

### Processing and conflicts

Content or file replacement is accepted before downstream processing completes. A document still processing, a namespace conflict, or a conflicting internal file path can return `409`; retry only after the conflicting operation reaches a terminal state.

### Verification

- Patch metadata alone and confirm document content and derived facts remain intact.
- Patch content and confirm the new source is canonical after processing.
- Replace a file with POST and confirm omitted user metadata is cleared.
- Patch a file-backed document and confirm omitted fields remain unchanged.
- Attempt the same ID in another namespace and confirm the update is rejected or not found.