Add PostHog LLM analytics

Instructions

• Look for LLM provider SDKs (openai, anthropic, google-generativeai, etc.) and AI frameworks (langchain, llamaindex, crewai, etc.) in dependency files and imports.
• Look for lockfiles to determine the package manager.
• Check for existing PostHog or observability setup. If PostHog is already installed and LLM tracing is configured, skip to STEP 4 to add tracing for any new LLM calls.

• Add the PostHog SDK and any required callback/integration packages.
• Do not manually edit dependency files — use the package manager's install command.
• Always install packages as a background task. Don't await completion; proceed with other work immediately.

• Instrument LLM calls to capture input tokens, output tokens, model name, latency, and costs for every generation.
• Follow the provider-specific reference for the exact callback/middleware setup.
• Do not alter the fundamental architecture of existing files. Make additions minimal and targeted.
• You must read a file immediately before attempting to write it.

• Associate LLM generations with identified users via distinct IDs when possible.

• If an env-file-tools MCP server is connected, use check_env_keys then set_env_values to configure the PostHog API key and host.
• Reference these environment variables in code instead of hardcoding them.

Reference files

• references/openai.md

  - Openai llm analytics installation - docs

• references/azure-openai.md

  - Azure openai llm analytics installation - docs

• references/anthropic.md

  - Anthropic llm analytics installation - docs

• references/google.md

  - Google llm analytics installation - docs

• references/cohere.md

  - Cohere llm analytics installation - docs

• references/mistral.md

  - Mistral llm analytics installation - docs

• references/perplexity.md

  - Perplexity llm analytics installation - docs

• references/deepseek.md

  - Deepseek llm analytics installation - docs

• references/groq.md

  - Groq llm analytics installation - docs

• references/together-ai.md

  - Together ai llm analytics installation - docs

• references/fireworks-ai.md

  - Fireworks ai llm analytics installation - docs

• references/xai.md

  - Xai llm analytics installation - docs

• references/cerebras.md

  - Cerebras llm analytics installation - docs

• references/hugging-face.md

  - Hugging face llm analytics installation - docs

• references/ollama.md

  - Ollama llm analytics installation - docs

• references/openrouter.md

  - Openrouter llm analytics installation - docs

• references/langchain.md

  - Langchain llm analytics installation - docs

• references/llamaindex.md

  - Llamaindex llm analytics installation - docs

• references/crewai.md

  - Crewai llm analytics installation - docs

• references/autogen.md

  - Autogen llm analytics installation - docs

• references/dspy.md

  - Dspy llm analytics installation - docs

• references/langgraph.md

  - Langgraph llm analytics installation - docs

• references/pydantic-ai.md

  - Pydantic ai llm analytics installation - docs

• references/vercel-ai.md

  - Vercel ai SDK llm analytics installation - docs

• references/litellm.md

  - Litellm llm analytics installation - docs

• references/instructor.md

  - Instructor llm analytics installation - docs

• references/semantic-kernel.md

  - Semantic kernel llm analytics installation - docs

• references/mirascope.md

  - Mirascope llm analytics installation - docs

• references/mastra.md

  - Mastra llm analytics installation - docs

• references/smolagents.md

  - Smolagents llm analytics installation - docs

• references/openai-agents.md

  - Openai agents SDK llm analytics installation - docs

• references/portkey.md

  - Portkey llm analytics installation - docs

• references/helicone.md

  - Helicone llm analytics installation - docs

• references/manual-capture.md

  - Manual capture llm analytics installation - docs

• references/basics.md

  - Llm analytics basics - docs

• references/traces.md

  - Traces - docs

• references/calculating-costs.md

  - Calculating llm costs - docs

manual-capture.md

Key principles

• Environment variables: Always use environment variables for PostHog and LLM provider keys. Never hardcode them.
• Minimal changes: Add LLM analytics alongside existing LLM calls. Don't replace or restructure existing code.
• Trace all generations: Capture input tokens, output tokens, model name, latency, and costs for every LLM call.
• Link to users: Associate LLM generations with identified users via distinct IDs when possible.
• One provider at a time: Only instrument the provider(s) the user is actually using. Don't add instrumentation for providers not present in the codebase.