385 lines
10 KiB
Markdown
385 lines
10 KiB
Markdown
# Function Calling Support
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This document describes the function calling format supported by the ik_llama.cpp server implementation.
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## Overview
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The server supports multiple native function calling formats including Kimi-K2, Qwen3 (XML), and DeepSeek R1. All function calls are automatically detected and converted to OpenAI-compatible responses.
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**⚠️ Model Requirements**: Function calling support is enabled for the following model types:
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- **Kimi-K2 models**: Models containing "kimi-k2" or "kimi_k2" in the model name
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- **Qwen3 models**: Models containing "qwen3", "qwen-3", or "qwen_3" in the model name
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- **DeepSeek R1 models**: Models containing "deepseek-r1", "deepseek_r1", or similar patterns
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Other models will not have tool injection or function call parsing enabled.
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## Supported Formats
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### Kimi-K2 Native Token Format
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**Detection Pattern:** `<|tool_calls_section_begin|>...<|tool_calls_section_end|>`
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**Structure:**
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```
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<|tool_calls_section_begin|>
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<|tool_call_begin|>
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functions.{name}:{index}<|tool_call_argument_begin|>
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{JSON arguments}
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<|tool_call_end|>
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<|tool_calls_section_end|>
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```
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**Example:**
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```
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<|tool_calls_section_begin|>
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<|tool_call_begin|>
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functions.get_weather:0<|tool_call_argument_begin|>
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{"location": "Tokyo"}
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<|tool_call_end|>
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<|tool_calls_section_end|>
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```
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**Notes:**
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- Native Kimi-K2 token format
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- Multiple function calls supported with different indices
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- Arguments are JSON objects
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- Function names follow `functions.{name}:{index}` pattern
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### XML-Style Format (Fallback)
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**Detection Pattern:** `<tool_call>...<invoke name="...">...<parameter name="...">...</parameter>...</invoke></tool_call>`
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**Structure:**
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```xml
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<tool_call>
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<invoke name="{function_name}">
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<parameter name="{param_name}">{param_value}</parameter>
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<parameter name="{param_name}">{param_value}</parameter>
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</invoke>
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</tool_call>
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```
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**Example:**
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```xml
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<tool_call>
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<invoke name="Write">
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<parameter name="file_path">/path/to/file.txt</parameter>
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<parameter name="content">File content here</parameter>
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</invoke>
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</tool_call>
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```
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**Notes:**
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- XML-style format as fallback when model generates this format instead of token format
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- Parameters are extracted as key-value pairs
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- Automatically converted to JSON arguments
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### DeepSeek R1 Native Format
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**Detection Pattern:** Multiple formats supported with automatic fallback
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**⚠️ Critical Implementation Note:** DeepSeek R1 models generate different formats depending on context. The parser handles all variants automatically.
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#### Format 1: Full Native Format (Primary)
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**Pattern:** `<|tool▁calls▁begin|>...<|tool▁calls▁end|>`
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```
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<|tool▁calls▁begin|>
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<|tool▁call▁begin|>
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function<|tool▁sep|>{function_name}
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```json
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{JSON arguments}
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```
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<|tool▁call▁end|>
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<|tool▁calls▁end|>
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```
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#### Format 2: Simplified Format (Fallback)
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**Pattern:** `function<{function_name}>`
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```
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function<get_weather>
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```json
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{"location": "Tokyo"}
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```
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```
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#### Format 3: Tools Array Format (New - July 2025)
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**Pattern:** `function\n```json\n{"tools": [...]}`
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```
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function
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```json
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{
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"tools": [
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{
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"name": "get_weather",
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"arguments": {
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"location": "Tokyo"
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}
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},
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{
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"name": "Read",
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"arguments": {
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"file_path": "/path/to/file.java"
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}
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}
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]
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}
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```
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```
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#### Format 4: XML Wrapped Format (New - July 2025)
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**Pattern:** `<tool_call>function</think>{function_name}\n```json\n{...}\n```</tool_call>`
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```
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<tool_call>
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function</think>Read
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```json
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{
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"file_path": "/path/to/example.txt"
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}
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```
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</tool_call>
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```
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**Notes:**
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- XML wrapper contains function name after `function</think>`
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- Single function call per XML block
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- JSON arguments within ```json``` code blocks
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- Handles reasoning text before function name
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**Examples:**
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Format 1 (Full):
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```
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<|tool▁calls▁begin|>
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<|tool▁call▁begin|>
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function<|tool▁sep|>get_weather
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```json
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{"location": "Tokyo"}
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```
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<|tool▁call▁end|>
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<|tool▁calls▁end|>
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```
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Format 2 (Simplified):
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```
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function<Read>
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```json
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{"file_path": "/path/to/file.txt"}
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```
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```
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Format 3 (Tools Array):
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```
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function
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```json
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{
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"tools": [
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{
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"name": "Read",
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"arguments": {
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"file_path": "/path/to/example/SystemProcessor.java"
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}
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},
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{
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"name": "Edit",
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"arguments": {
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"file_path": "/path/to/file.java",
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"old_string": "old code",
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"new_string": "new code"
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}
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}
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]
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}
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```
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```
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Format 4 (XML Wrapped):
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```
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<tool_call>
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function</think>CompleteTask
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```json
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{
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"status": "completed"
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}
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```
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</tool_call>
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```
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**Implementation Notes:**
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- **Reasoning Support**: All formats support `<think>...</think>` reasoning tags (automatically extracted)
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- **Multiple Tool Calls**: Format 1 & 2 use separate blocks, Format 3 uses array structure, Format 4 uses single XML block
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- **Automatic Detection**: Parser tries formats in order: Format 3 → Format 4 → Format 1 → Format 2
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- **Original llama.cpp Base**: Implementation follows original llama.cpp patterns exactly
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- **Status**: All formats ✅ Working (July 2025 update)
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## OpenAI-Compatible Output
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The native format is converted to the standard OpenAI function calling response:
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```json
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{
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"choices": [
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{
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"finish_reason": "tool_calls",
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"message": {
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"role": "assistant",
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"content": "filtered_content_without_function_calls",
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"tool_calls": [
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{
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"id": "functions.get_weather:0",
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"type": "function",
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"function": {
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"name": "get_weather",
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"arguments": "{\"location\": \"Tokyo\"}"
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}
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}
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]
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}
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}
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]
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}
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```
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## Implementation Details
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### Content Filtering
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When function calls are detected:
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- Function call syntax is removed from content
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- Tool calls are extracted into separate array
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- Content is cleaned for display
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### Error Handling
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- Missing tokens in format returns empty array
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- Malformed structure returns empty array
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- Parser gracefully handles invalid JSON in arguments
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## Usage with Tools Parameter
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To enable function calling, include the `tools` parameter in your request:
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```json
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{
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"model": "kimi-k2",
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"messages": [
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{
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"role": "user",
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"content": "What's the weather in Tokyo?"
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}
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],
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"tools": [
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{
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"type": "function",
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"function": {
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"name": "get_weather",
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"description": "Get weather information for a location",
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"parameters": {
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"type": "object",
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"properties": {
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"location": {
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"type": "string",
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"description": "The city and state, e.g. San Francisco, CA"
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}
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},
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"required": ["location"]
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}
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}
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}
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]
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}
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```
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## Model Compatibility
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- **Kimi-K2 models**: Native support with token format
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- **Qwen3 models**: Native support with XML format (Hermes-style)
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- **DeepSeek R1 models**: Native support with reasoning and function call format (ported from original llama.cpp)
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- **Other models**: No function calling support
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## Testing
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Comprehensive test suite for all supported formats:
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### Unit Tests
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- **File**: `tests/test-function-calls.cpp`
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- **Coverage**: All supported model formats (Kimi-K2, Qwen3, DeepSeek R1)
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- **Test Types**:
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- Native format parsing for each model type
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- Multiple function calls
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- Error handling and malformed input
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- Streaming and non-streaming responses
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- Content extraction and cleaning
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- OpenAI-compatible output generation
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### DeepSeek R1 Specific Tests
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- **Format 1 Tests**: Full native format with separators ✅
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- **Format 2 Tests**: Simplified format without separators ✅
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- **Format 3 Tests**: Tools array format ✅ (Fixed July 2025)
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- **Format 4 Tests**: XML wrapped format ✅ (Added July 2025)
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- **Integration Tests**: Server-to-parser call chain verification
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- **Regression Tests**: Ensure existing formats continue working
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### Running Tests
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```bash
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# Build tests
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cd build && make test-function-calls -j$(nproc)
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# Run all function call tests
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./bin/test-function-calls
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# Run DeepSeek R1 specific tests
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./bin/test-function-calls | grep -E "(DeepSeek|tool_calls_count)"
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# Check Format 3 specific issues
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./bin/test-function-calls | grep -A5 -B5 "Real failing format"
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```
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### Test Status
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- **Kimi-K2**: ✅ All tests passing
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- **Qwen3 XML**: ✅ All tests passing
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- **DeepSeek R1 Format 1 & 2**: ✅ All tests passing
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- **DeepSeek R1 Format 3**: ✅ All tests passing (Fixed July 2025)
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- **DeepSeek R1 Format 4**: ✅ All tests passing (Added July 2025)
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## File Structure
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### Server Integration
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- **`examples/server/server.cpp`** - Main server entry point, calls `parse_chat_message_incremental()`
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- **`examples/server/function_calls.hpp`** - Server-side parser creation and integration
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- **`examples/server/utils.hpp`** - Server utilities (includes function_calls.hpp)
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### Core Parsing Engine
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- **`common/chat-parser.cpp`** - Main parser routing, delegates to model-specific parsers
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- **`common/chat-parser.h`** - Parser interface and JSON parsing infrastructure
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- **`common/chat.cpp`** - Model-specific parsing implementations:
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- `common_chat_parse_kimi_k2()` - Kimi-K2 native format
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- `common_chat_parse_qwen3()` - Qwen3 XML format
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- `common_chat_parse_deepseek_r1()` - DeepSeek R1 multiple formats
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- `parse_deepseek_r1_tools_array()` - Format 3 tools array parser
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- `parse_deepseek_r1_xml_wrapped()` - Format 4 XML wrapper parser
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- **`common/chat.h`** - Function declarations and model detection
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### Testing
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- **`tests/test-function-calls.cpp`** - Comprehensive unit tests for all formats
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- **`tests/get-model.cpp`** - Test utilities for model loading
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### Integration Flow
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```
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server.cpp:2832
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↓ parse_chat_message_incremental(generated_text, false, modelname)
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function_calls.hpp:94-95
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↓ common_chat_msg_parser.parse()
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chat-parser.cpp:140
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↓ model detection → specific parser
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chat.cpp
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↓ common_chat_parse_deepseek_r1() / kimi_k2() / qwen3()
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↓ Format detection → regex matching → JSON parsing → tool_calls array
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```
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### Key Implementation Files
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- **DeepSeek R1 Format 3**: `common/chat.cpp:291-332` (`parse_deepseek_r1_tools_array`)
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- **DeepSeek R1 Format 4**: `common/chat.cpp:335-374` (`parse_deepseek_r1_xml_wrapped`)
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- **Exception handling**: `common/chat.cpp:222-289` (Format 3 → 4 → 1 → 2 fallback chain)
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- **Model detection**: `common/chat.cpp` (`is_deepseek_r1_model`, `is_qwen3_model`, etc.)
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- **Comprehensive tests**: `tests/test-function-calls.cpp` (All formats with TDD coverage) |