# Limits
URL: /docs/cloud/limits

Every limit a project enforces, in one place.

> For AI agents: a documentation index is available at [llms.txt](/llms.txt). Use `.md` for canonical markdown pages; `.mdx` is kept as a backwards-compatible alias on supported URL paths.

Most limits protect the project from an accidental flood and are the same on every plan; the per project numbers at the end vary by plan. The caps on active users and on thread titles are on [Plans and pricing](/docs/cloud/pricing).

## Rate limits

| What                            | Limit        | Keyed by       |
| ------------------------------- | ------------ | -------------- |
| Creating an anonymous session   | 30 a minute  | client address |
| Refreshing an anonymous session | 120 a minute | client address |
| Engagement events               | 600 a minute | user           |

A limited request answers `429 { "error": "rate_limited" }` with a `Retry-After` header. Threads, messages, run reports, scores, traces, the project read API and MCP are not rate limited.

## Request sizes

| Object                                                      | Limit                                   |
| ----------------------------------------------------------- | --------------------------------------- |
| Thread title                                                | 255 characters                          |
| Thread `external_id`                                        | 255 characters                          |
| Thread `metadata`                                           | 16 keys; keys 64 characters, values 512 |
| Message `content`                                           | 64 KB serialized                        |
| Messages deleted per request                                | 200                                     |
| Run `error` and `error_code`                                | 2,048 and 64 characters                 |
| Run `tags`                                                  | 20 tags of 64 characters                |
| Run `environment` and `release`                             | 64 and 255 characters                   |
| Run `attributes`                                            | 16 KB                                   |
| Run `steps`, `tool_calls` and `sampling_calls`              | 1,000 entries each                      |
| Run `output_text`, tool arguments, tool results, step input | 50,000 characters each                  |
| Token counts                                                | up to 100,000,000                       |
| Events per request                                          | 50                                      |
| Event `props`                                               | 1 KB; keys 64 characters, strings 256   |
| Event ids                                                   | 48 characters                           |
| Score `name` and `comment`                                  | 64 and 2,000 characters                 |
| Score `string_value`                                        | 255 characters                          |
| Attachment                                                  | 25 MB, one of the accepted types        |
| Trace export                                                | 4 MB per request, 500 spans per trace   |
| Span attributes                                             | 16 KB                                   |
| Allowed origins                                             | 32 entries of 255 characters            |
| `Aui-Sdk` header                                            | 8 tokens                                |

A run report or a trace export that exceeds a size limit is refused with `400` or `413`; oversized tags and attributes on a report are refused rather than trimmed.

## List pages

| List                           | Default          | Maximum  |
| ------------------------------ | ---------------- | -------- |
| `GET /v1/threads`              | 20               | 100      |
| `GET /v1/threads/:id/messages` | 200              | 200      |
| `GET /v1/projects/runs`        | 50               | 100      |
| `GET /v1/projects/scores`      | 50               | 200      |
| `GET /v1/projects/usage/daily` | the last 30 days | 366 days |
| Dashboard tables               | 50 rows          | 100 rows |

## Time

| What                               | Value                                                                                |
| ---------------------------------- | ------------------------------------------------------------------------------------ |
| Anonymous refresh token            | 30 days, extended by 30 days on every refresh                                        |
| Access token                       | 5 minutes                                                                            |
| API key expiry                     | never, or 7, 30, 90 or 365 days                                                      |
| Presigned upload and download URLs | 15 minutes                                                                           |
| Retention                          | 7 to 365 days from the presets, or forever; a shorter setting applies after 24 hours |
| Alert cooldown                     | 5 minutes to 7 days                                                                  |
| SDK client list                    | entries not seen for 180 days drop off                                               |

## Per project

| What                               | Limit                                                         |
| ---------------------------------- | ------------------------------------------------------------- |
| Alert rules                        | 1, 20 or 100 by plan                                          |
| Thread titles on the cloud's model | 500 or 5,000 included a month by plan; unlimited from Startup |
| Evaluators                         | 20                                                            |
| Evaluator categories               | 10 per rule                                                   |
| Thread title length                | 2 to 12 words                                                 |
| Intelligence topic ceiling         | 10 to 60                                                      |
| Test user prefixes                 | 10                                                            |