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

# Quality Gate

> How MemoryOS filters low-value or risky write traffic before it becomes memory.

Every `add()` call passes through a four-layer gate before extraction is queued. Blocked calls return HTTP `200` with a `status` indicating the blocking layer — inspect the body, not just the status code.

## Layers

| Layer | What it checks                                          | Block reason          |
| ----- | ------------------------------------------------------- | --------------------- |
| `L1`  | Per-user rate limit — requests per minute               | `rate_limit_exceeded` |
| `L2`  | Content quality — score below 0.35                      | `low_quality`         |
| `L3`  | Semantic dedup — similarity above 0.92                  | `duplicate_query`     |
| `L4`  | Budget — tenant monthly quota exhausted on block policy | `budget_exhausted`    |

## What gets blocked

| Layer | Example input                                    |
| ----- | ------------------------------------------------ |
| `L1`  | Same user sends many writes in one minute        |
| `L2`  | `"ok"`, `"hi"`, `"??"`                           |
| `L3`  | Sending the same preference statement repeatedly |
| `L4`  | Tenant is out of monthly calls or tokens         |

## Quality scoring

The L2 score is based on message count, average message length, lexical diversity, and whether the conversation contains a question signal. Short or content-free messages score poorly.

## How to keep block rates low

* Send meaningful facts, preferences, goals, or procedures rather than filler text.
* Don't send the same memory-worthy statement on every turn.
* Batch coherent conversational turns instead of single-word fragments.
* Watch `blocked_reason` and `budget_remaining_pct` on `add()` responses.