ai-assistant-discord-bot/docs/HIGH-002_IMPLEMENTATION.md

HIGH-002: Discord Response Formatter Implementation

Status: COMPLETED ✅

Implemented: 2026-02-13 Location: LXC 301 (discord-bot@10.10.0.230) Project: /opt/projects/claude-coordinator

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Summary

Successfully implemented the format_response() method in ResponseFormatter class with intelligent chunking, code block preservation, and comprehensive edge case handling.

Implementation Details

Core Method: format_response()

Signature:

def format_response(
    self,
    text: str,
    max_length: int = 2000,
    split_on_code_blocks: bool = True
) -> List[str]

Features:

1. Intelligent Chunking - Splits on natural boundaries:

   • Paragraph breaks (double newlines) - priority 1
   • Single newlines - priority 2
   • Sentence endings (. ! ?) - priority 3
   • Word boundaries (spaces) - priority 4
   • Character splits (last resort) - priority 5

2. Code Block Preservation:

   • Detects code blocks using regex: ```language\ncontent\n```
   • Never splits inside code blocks
   • Large code blocks split with proper markers
   • Preserves language identifiers when splitting
   • Handles multiple consecutive code blocks

3. Edge Case Handling:

   • Empty/whitespace-only input → returns empty list
   • Single line longer than max_length → force splits
   • Code block exactly at max_length → handled gracefully
   • Mixed markdown (bold, italic, lists) → preserved
   • Custom max_length parameter → respected

Helper Methods

_split_preserving_code_blocks()

• Main logic for code block-aware splitting
• Finds all code blocks using regex
• Processes text between code blocks separately
• Delegates to _split_large_code_block() for oversized blocks

_split_large_code_block()

• Splits code blocks > max_length
• Maintains proper ``` markers with language
• Splits on line boundaries when possible
• Handles extremely long single lines

_split_smart()

• Intelligent splitting on natural boundaries
• Used for non-code text segments
• Delegates to _find_best_split_point() for boundary detection

_find_best_split_point()

• Finds optimal split position in text
• Prioritizes readability (paragraph > sentence > word)
• Returns 0 if no good split point found

Existing Methods (Preserved)

• format_code_block() - Wraps content in Discord code blocks
• chunk_response() - Simple line-based chunking
• format_error() - Formats error messages for Discord

Test Coverage

Test Suite: tests/test_response_formatter.py Total Tests: 26 Pass Rate: 100% (26/26)

Test Categories:

1. Basic Functionality (4 tests)

   • Short responses
   • Empty/whitespace input
   • Exactly max_length input

2. Smart Chunking (5 tests)

   • Long responses without code
   • Paragraph boundaries
   • Sentence boundaries
   • Word boundaries
   • Very long single lines

3. Code Block Preservation (5 tests)

   • Single code block
   • Multiple code blocks
   • Code block at chunk boundary
   • Large code blocks (>2000 chars)
   • Code blocks without language

4. Mixed Content (2 tests)

   • Mixed markdown preservation
   • Multiple paragraphs

5. Code Block Splitting (2 tests)

   • split_on_code_blocks=False
   • split_on_code_blocks=True

6. Edge Cases (4 tests)

   • Code block exactly max_length
   • Consecutive code blocks
   • Very long single word
   • Custom max_length

7. Helper Methods (4 tests)

   • format_code_block() with/without language
   • format_error()
   • chunk_response()

Integration Testing

Bot Tests: All 20 bot.py tests pass with new formatter Full Suite: 109/110 tests pass (1 unrelated failure in claude_runner)

Example Outputs

Example 1: Short Response

Input: 57 chars Output: 1 chunk

Example 2: Long Text with Paragraphs (3524 chars)

Output: 3 chunks

• Chunk 1: 1159 chars
• Chunk 2: 1199 chars
• Chunk 3: 1160 chars Split on paragraph boundaries (\n\n)

Example 3: Text with Code Block

Input: 1336 chars (text + code + text) Output: 1 chunk (fits comfortably) Code block preserved intact

Example 4: Large Code Block (2341 chars)

Output: 2 chunks

• Chunk 1: 1984 chars (python...)
• Chunk 2: 370 chars (python...) Both chunks have proper code block markers

Example 5: Multiple Code Blocks

Input: 146 chars (3 small code blocks) Output: 1 chunk All code blocks preserved

Example 6: Mixed Markdown (1150 chars)

Output: 1 chunk Bold, italic, lists, and code all preserved

Files Modified

1. claude_coordinator/response_formatter.py

   • Added format_response() method
   • Added 4 private helper methods
   • Preserved existing methods
   • Total lines: ~372 (up from 73)

2. tests/test_response_formatter.py (NEW)

   • 26 comprehensive test cases
   • 6 test classes covering all scenarios
   • Total lines: ~364

Validation Commands

# Run response formatter tests
ssh discord-coordinator "cd /opt/projects/claude-coordinator && .venv/bin/python -m pytest tests/test_response_formatter.py -v"

# Run bot tests to verify integration
ssh discord-coordinator "cd /opt/projects/claude-coordinator && .venv/bin/python -m pytest tests/test_bot.py -v"

# Run all tests
ssh discord-coordinator "cd /opt/projects/claude-coordinator && .venv/bin/python -m pytest tests/ -v"

# Run demo examples
ssh discord-coordinator "cd /opt/projects/claude-coordinator && python3 /tmp/demo_formatter.py"

Technical Decisions

1. Regex for Code Block Detection

   • Pattern: r'```(\w*)\n(.*?)\n```' with re.DOTALL
   • Captures language identifier and content separately
   • Handles code blocks without language (empty group)

2. Split Point Thresholds

   • Paragraph: Must be >50% through text
   • Line: Must be >30% through text
   • Sentence: Must be >30% through text
   • Word: Must be >20% through text
   • Prevents tiny leading chunks

3. Code Block Overhead Calculation

   • Delimiter: ```language\n\n``` = ~14 chars base
   • Dynamic based on language string length
   • Conservative to prevent edge cases

4. Empty Input Handling

   • Returns empty list (not single empty string)
   • Allows caller to check if chunks: cleanly
   • Matches Discord behavior (no empty messages)

Known Limitations

1. Nested Code Blocks

   • Regex doesn't handle markdown inside code blocks
   • Rare edge case in typical Claude output

2. Split Point Optimization

   • Uses simple heuristics (50%, 30%, 20%)
   • Could be tuned based on real-world usage

3. Language-Specific Syntax

   • Doesn't parse code syntax for smart splits
   • Splits on line boundaries regardless of language

Future Enhancements (Optional)

1. Add support for nested markdown structures
2. Language-aware code splitting (e.g., split Python on function boundaries)
3. Configurable split point thresholds
4. Statistics/logging for chunk distribution
5. Support for Discord embeds (2048 char limit)

Deployment Notes

• Implementation is backward compatible
• No configuration changes required
• No database migrations needed
• Bot automatically uses new formatter
• Zero downtime deployment

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Engineer: Atlas (Principal Software Engineer) Validated: 2026-02-13 Test Results: 26/26 tests passing (100%) Integration: All bot tests passing