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

# crystal_edit

> Update an existing memory in Memory Crystal.

## What it does

Updates an existing memory by its ID, allowing you to correct errors, add new information, change memory classification, or update tags. Only the fields you provide will be modified; unspecified fields remain unchanged.

## Parameters

| Parameter | Type      | Required | Default | Description                                                                                                  |
| --------- | --------- | -------- | ------- | ------------------------------------------------------------------------------------------------------------ |
| memoryId  | string    | Yes      | —       | ID of the memory to update                                                                                   |
| title     | string    | No       | —       | New title for the memory                                                                                     |
| content   | string    | No       | —       | New content body                                                                                             |
| tags      | string\[] | No       | —       | New array of tags                                                                                            |
| store     | string    | No       | —       | New memory store: `sensory`, `episodic`, `semantic`, `procedural`, or `prospective`                          |
| category  | string    | No       | —       | New category: `decision`, `lesson`, `person`, `rule`, `event`, `fact`, `goal`, `workflow`, or `conversation` |

## Returns

```json theme={"system"}
{
  "success": true,
  "memoryId": "string",
  "message": "Updated memory {memoryId}"
}
```

**Field descriptions:**

* `success` — Whether the update succeeded
* `memoryId` — The updated memory's ID (echo of input)
* `message` — Confirmation message

## Examples

### Basic usage

```javascript theme={"system"}
// Fix a typo in an existing memory
crystal_edit({
  memoryId: "abc123def456",
  content: "Use PostgreSQL for session storage because concurrent writes are needed"
})

// Result:
// {
//   "success": true,
//   "memoryId": "abc123def456",
//   "message": "Updated memory abc123def456"
// }
```

### Advanced usage

```javascript theme={"system"}
// Promote a lesson from sensory to semantic store and retag
crystal_edit({
  memoryId: "xyz789",
  store: "semantic",
  category: "lesson",
  tags: ["postgres", "reliability", "database-choice"],
  title: "PostgreSQL concurrency vs SQLite lock contention"
})

// Move a fact to a different category and update content
crystal_edit({
  memoryId: "mem_abc",
  category: "rule",
  content: "Always use prepared statements to prevent SQL injection"
})
```

## When to use this vs alternatives

* **`crystal_edit`** — When you know the exact memory ID and want to modify it surgically
* **`crystal_remember`** — When you want to save a new memory (not update existing)
* **`crystal_forget`** — When you want to remove or archive a memory instead of editing it

## Error handling

| Error                  | Cause                               | Resolution                                                                                          |
| ---------------------- | ----------------------------------- | --------------------------------------------------------------------------------------------------- |
| Invalid memoryId       | Missing, empty, or non-existent ID  | Provide a valid memory ID from recall results                                                       |
| Invalid store value    | Not one of the 5 allowed stores     | Use: `sensory`, `episodic`, `semantic`, `procedural`, or `prospective`                              |
| Invalid category value | Not one of the 9 allowed categories | Use: `decision`, `lesson`, `person`, `rule`, `event`, `fact`, `goal`, `workflow`, or `conversation` |
| tags is not an array   | Malformed tag input                 | Pass tags as `["tag1", "tag2"]`                                                                     |
| Authentication failed  | Invalid Convex JWT or API key       | Verify auth configuration in Convex client setup                                                    |
| Memory not found       | ID does not exist or was deleted    | Verify ID against recent recall results                                                             |

## Notes

* At least one field besides `memoryId` must be provided (editing nothing is a no-op)
* All string fields are trimmed of leading/trailing whitespace
* Category and store enums are case-sensitive and must match exactly
* Tags are deduplicated automatically on save
* Editing a memory updates its `lastAccessedAt` timestamp
* The update is transactional — either all fields succeed or the entire operation fails