# Source: https://docs.pipecat.ai/server/utilities/turn-management/filter-incomplete-turns.md

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

# Filter Incomplete User Turns

> Use LLM-based detection to suppress responses when users are cut off mid-thought

## Overview

Filter Incomplete Turns is an LLM-powered feature that detects when a user's conversational turn was incomplete (they were cut off or need time to think) and suppresses the bot's response accordingly. Instead of responding to partial input, the bot waits for the user to continue, then automatically re-engages if they remain silent.

This creates more natural conversations by:

* Preventing the bot from responding to incomplete thoughts
* Giving users time to finish speaking without interruption
* Automatically prompting users to continue after pauses

## How It Works

When enabled, the LLM outputs a turn completion marker as the first character of every response:

| Marker | Meaning                                              | Bot Behavior                             |
| ------ | ---------------------------------------------------- | ---------------------------------------- |
| `✓`    | **Complete** - User finished their thought           | Respond normally                         |
| `○`    | **Incomplete Short** - User was cut off mid-sentence | Suppress response, wait 5s, then prompt  |
| `◐`    | **Incomplete Long** - User needs time to think       | Suppress response, wait 10s, then prompt |

The system automatically:

1. Injects turn completion instructions into the LLM's system prompt
2. Detects markers in the LLM's streaming response
3. Suppresses bot speech for incomplete turns
4. Starts a timeout based on the incomplete type
5. Re-prompts the LLM when the timeout expires

## Configuration

Enable the feature via `LLMUserAggregatorParams` when creating an `LLMContextAggregatorPair`:

```python  theme={null}
from pipecat.processors.aggregators.llm_context import LLMContext
from pipecat.processors.aggregators.llm_response_universal import (
    LLMContextAggregatorPair,
    LLMUserAggregatorParams,
)

context = LLMContext(messages)
user_aggregator, assistant_aggregator = LLMContextAggregatorPair(
    context,
    user_params=LLMUserAggregatorParams(
        filter_incomplete_user_turns=True,
    ),
)
```

### LLMUserAggregatorParams

<ParamField path="filter_incomplete_user_turns" type="bool" default="False">
  Enable LLM-based turn completion detection. When True, the system
  automatically injects turn completion instructions into the LLM context and
  configures the LLM service to process turn markers.
</ParamField>

<ParamField path="user_turn_completion_config" type="UserTurnCompletionConfig" default="None">
  Optional configuration object for customizing turn completion behavior. If not
  provided, default values are used.
</ParamField>

## UserTurnCompletionConfig

Use `UserTurnCompletionConfig` to customize timeouts, prompts, and instructions:

```python  theme={null}
from pipecat.turns.user_turn_completion_mixin import UserTurnCompletionConfig

user_aggregator, assistant_aggregator = LLMContextAggregatorPair(
    context,
    user_params=LLMUserAggregatorParams(
        filter_incomplete_user_turns=True,
        user_turn_completion_config=UserTurnCompletionConfig(
            incomplete_short_timeout=5.0,
            incomplete_long_timeout=10.0,
            incomplete_short_prompt="Custom prompt for short pauses...",
            incomplete_long_prompt="Custom prompt for long pauses...",
            instructions="Custom turn completion instructions...",
        ),
    ),
)
```

### Parameters

<ParamField path="incomplete_short_timeout" type="float" default="5.0">
  Seconds to wait after detecting `○` (incomplete short) before re-prompting the
  LLM. Use shorter values for more responsive re-engagement.
</ParamField>

<ParamField path="incomplete_long_timeout" type="float" default="10.0">
  Seconds to wait after detecting `◐` (incomplete long) before re-prompting the
  LLM. Use longer values to give users more time to think.
</ParamField>

<ParamField path="incomplete_short_prompt" type="str" default="...">
  System prompt sent to the LLM when the short timeout expires. Should instruct
  the LLM to generate a brief, natural prompt encouraging the user to continue.
</ParamField>

<ParamField path="incomplete_long_prompt" type="str" default="...">
  System prompt sent to the LLM when the long timeout expires. Should instruct
  the LLM to generate a friendly check-in message.
</ParamField>

<ParamField path="instructions" type="str" default="...">
  Complete turn completion instructions appended to the system prompt. Override
  this to customize how the LLM determines turn completeness.
</ParamField>

## Markers Explained

### Complete (✓)

The user has provided enough information for a meaningful response:

```
User: "I'd go to Japan because I love the culture and food."
LLM: "✓ Japan is a wonderful choice! The blend of ancient traditions..."
```

The `✓` marker tells the system to push the response normally. The marker itself is not spoken (marked with `skip_tts`).

### Incomplete Short (○)

The user was cut off mid-sentence and will likely continue soon:

```
User: "I'd go to Japan because I love"
LLM: "○"
```

The `○` marker suppresses the bot's response entirely. After 5 seconds (configurable), the LLM is prompted to re-engage with something like "Go ahead, I'm listening."

### Incomplete Long (◐)

The user needs more time to think or explicitly asked for time:

```
User: "That's a good question. Let me think..."
LLM: "◐"
```

The `◐` marker also suppresses the response, but waits 15 seconds (configurable) before prompting. This handles cases like:

* "Hold on a second"
* "Let me think about that"
* "Hmm, that's interesting..."

## Usage Examples

### Basic Usage

Enable turn completion with default settings:

```python  theme={null}
from pipecat.processors.aggregators.llm_context import LLMContext
from pipecat.processors.aggregators.llm_response_universal import (
    LLMContextAggregatorPair,
    LLMUserAggregatorParams,
)

messages = [
    {
        "role": "system",
        "content": "You are a helpful assistant...",
    }
]

context = LLMContext(messages)
user_aggregator, assistant_aggregator = LLMContextAggregatorPair(
    context,
    user_params=LLMUserAggregatorParams(
        filter_incomplete_user_turns=True,
    ),
)
```

<Note>
  You don't need to modify your system prompt. Turn completion instructions are
  automatically appended when `filter_incomplete_user_turns` is enabled.
</Note>

### Custom Timeouts

Adjust timeouts for your use case:

```python  theme={null}
from pipecat.turns.user_turn_completion_mixin import UserTurnCompletionConfig

user_aggregator, assistant_aggregator = LLMContextAggregatorPair(
    context,
    user_params=LLMUserAggregatorParams(
        filter_incomplete_user_turns=True,
        user_turn_completion_config=UserTurnCompletionConfig(
            incomplete_short_timeout=3.0,  # More responsive
            incomplete_long_timeout=20.0,  # More patient
        ),
    ),
)
```

### Custom Prompts

Customize what the LLM says when re-engaging:

```python  theme={null}
user_aggregator, assistant_aggregator = LLMContextAggregatorPair(
    context,
    user_params=LLMUserAggregatorParams(
        filter_incomplete_user_turns=True,
        user_turn_completion_config=UserTurnCompletionConfig(
            incomplete_short_prompt="""The user paused briefly.
Generate a contextual prompt to encourage them to continue.
Respond with ✓ followed by your message.""",
            incomplete_long_prompt="""The user has been quiet for a while.
Generate a friendly check-in.
Respond with ✓ followed by your message.""",
        ),
    ),
)
```

<Warning>
  Custom prompts must instruct the LLM to respond with `✓` followed by the
  message. This ensures the re-engagement message is spoken normally.
</Warning>

### With Smart Turn Detection

Combine with smart turn detection for better end-of-turn detection:

```python  theme={null}
from pipecat.audio.turn.smart_turn.local_smart_turn_v3 import LocalSmartTurnAnalyzerV3
from pipecat.turns.user_stop import TurnAnalyzerUserTurnStopStrategy
from pipecat.turns.user_turn_strategies import UserTurnStrategies

user_aggregator, assistant_aggregator = LLMContextAggregatorPair(
    context,
    user_params=LLMUserAggregatorParams(
        user_turn_strategies=UserTurnStrategies(
            stop=[
                TurnAnalyzerUserTurnStopStrategy(
                    turn_analyzer=LocalSmartTurnAnalyzerV3()
                )
            ]
        ),
        filter_incomplete_user_turns=True,
    ),
)
```

<Tip>
  Smart turn detection helps determine when the user stops speaking, while turn
  completion filtering determines whether to respond. They work well together
  for natural conversations.
</Tip>

## Transcripts

Turn completion markers are automatically stripped from assistant transcripts emitted via the `on_assistant_turn_stopped` event. Your transcript handlers will receive clean text without markers:

```python  theme={null}
@assistant_aggregator.event_handler("on_assistant_turn_stopped")
async def on_assistant_turn_stopped(aggregator, message: AssistantTurnStoppedMessage):
    # message.content will be "Japan is a wonderful choice!"
    # NOT "✓ Japan is a wonderful choice!"
    print(f"Assistant: {message.content}")
```

## Supported LLM Services

Turn completion detection works with any LLM service that inherits from `LLMService`:

* OpenAI (`OpenAILLMService`)
* Anthropic (`AnthropicLLMService`)
* Google Gemini (`GoogleLLMService`)
* AWS Bedrock (`AWSLLMService`)
* And other compatible services

## Graceful Degradation

If the LLM fails to output a turn marker:

1. The system logs a warning indicating markers were expected but not found
2. The buffered text is pushed normally to avoid losing the response
3. The conversation continues without interruption

This ensures the feature doesn't break conversations if the LLM occasionally disobeys instructions.

## Related

* [User Turn Strategies](/server/utilities/turn-management/user-turn-strategies) - Configure turn detection
* [Smart Turn Detection](/server/utilities/smart-turn/smart-turn-overview) - AI-powered end-of-turn detection
* [Transcriptions](/server/utilities/turn-management/transcriptions) - Working with conversation transcripts