Streaming UI Hooks Module

Progressive display for thinking blocks, tool invocations, and token usage in the Amplifier console.

Purpose

Display streaming LLM output (thinking blocks, tool calls, and token usage) to console with configurable formatting and truncation.

Contract

Inputs

• content_block:start events - Detect start of thinking blocks
• content_block:delta events - Track thinking block progress (not displayed)
• content_block:end events - Display complete thinking blocks
• tool:pre events - Display tool invocations
• tool:post events - Display tool results
• llm:response events - Display token usage statistics

Outputs

• Formatted console output via print statements
• No data transformations or system state changes

Side Effects

• Console output only (print statements to stdout)

Dependencies

• amplifier-core - For events, coordinator, and HookResult types
• Standard library only (no external dependencies)

Configuration

Configure via profile.ui section:

[ui]
show_thinking_stream = true  # Display thinking blocks (default: true)
show_tool_lines = 5          # Max lines to show for tool I/O (default: 5)
show_token_usage = true      # Display token usage after each turn (default: true)

Features

• Thinking Block Display: Shows formatted thinking blocks with clear visual boundaries
• Tool Invocation Display: Shows tool name and truncated arguments
• Tool Result Display: Shows success/failure status with truncated output
• Token Usage Display: Shows input/output/total token counts after each LLM response
• Configurable Truncation: Limit tool I/O display to configured line count
• Clean Formatting: Visual separators and icons for better readability

Events Hooked

Event	Purpose	Action
content_block:start	Detect thinking block start	Display "Thinking..." indicator
content_block:end	Receive complete thinking block	Display formatted thinking content
tool:pre	Tool invocation	Display tool name and arguments
tool:post	Tool result	Display success/failure with output
llm:response	LLM response received	Display token usage statistics

Display Format

Thinking Blocks

🧠 Thinking...

============================================================
Thinking:
------------------------------------------------------------
[thinking content here]
============================================================

Tool Invocations

🔧 Using tool: tool_name
   Arguments: {truncated arguments}

✅ Tool result: tool_name
   {truncated output}

Token Usage

│  Input: 1,234 | Output: 567 | Total: 1,801
└─ 📊 Token Usage

Philosophy Compliance

✅ Zero kernel changes - Pure hooks implementation, no core modifications ✅ Pure observability - Only displays information, no behavior changes ✅ Configuration via profile - Uses standard profile.ui settings ✅ Simple, focused implementation - Single responsibility: console display ✅ Modular design - Self-contained module with clear contract

Testing

Run tests with:

cd amplifier-module-hooks-streaming-ui
pytest tests/

Regeneration Specification

This module can be fully regenerated from this README specification. Key invariants:

1. Mount function signature: async def mount(coordinator, config)
2. Hook registration on coordinator.hooks
3. Return HookResult with action="continue"
4. No state changes to system, only console output
5. Configuration from profile.ui section

Contributing

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Trademarks

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