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Documentation Index

Fetch the complete documentation index at: https://simplellmfunc.cn/llms.txt

Use this file to discover all available pages before exploring further.

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Observability

SimpleLLMFunc integrates with Langfuse for tracing LLM generations, tool calls, and agent sessions.

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Setup

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1. Install (included with SimpleLLMFunc)

Langfuse client is bundled. No extra install needed.

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2. Configure Environment

# .env
LANGFUSE_PUBLIC_KEY=pk-lf-...
LANGFUSE_SECRET_KEY=sk-lf-...
LANGFUSE_BASE_URL=https://cloud.langfuse.com
LANGFUSE_ENABLED=true
LANGFUSE_EXPORT_ALL_SPANS=true

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3. Use Normally

Once configured, tracing is automatic. Every decorated @llm_function and @llm_chat invocation creates:
  • A trace for the full invocation
  • Generations for each LLM call
  • Spans for tool executions

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What Gets Traced

ComponentLangfuse EntityContains
@llm_function callTraceFull invocation lifecycle
@llm_chat callTraceFull ReAct loop
Each LLM API callGenerationMessages in/out, tokens, latency
Each tool executionSpanTool name, args, result, duration
ReAct iterationsSpanIteration boundaries

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Trace IDs

Each invocation gets a unique trace_id propagated through all nested operations: 
from SimpleLLMFunc.logger import get_current_trace_id

# Inside a tool or custom code
trace_id = get_current_trace_id()

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Custom Trace Names

The trace name defaults to the decorated function name. Override with: 
@llm_function(llm_interface=llm)
async def my_func(text: str) -> str:
    """Process text."""
    pass

# The trace will be named "my_func" in Langfuse

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Flushing

Observations are batched and sent asynchronously. Force flush at shutdown: 
from SimpleLLMFunc.observability import flush_all_observations

await flush_all_observations()

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Disabling

Set LANGFUSE_ENABLED=false or simply don’t configure the keys. The framework gracefully degrades — no errors, just no traces.

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Log Levels

Control framework logging independently: 
LOG_LEVEL=WARNING   # Recommended: suppress noisy internal logs
LOG_DIR=logs        # File output location
Available levels: DEBUG, INFO, WARNING, ERROR, CRITICAL. Use DEBUG only when investigating framework behavior. WARNING is the recommended default for production.