ai-orchestration-langchain

# LangChain.js Patterns > **Quick Guide:** Use LangChain.js (v1.x) to build composable LLM applications. Use LCEL (`prompt.pipe(model).pipe(parser)`) for all chain composition -- never use legacy `LLMChain`. Use `withStructuredOutput(zodSchema)` for typed responses. Use `createAgent()` (LangGraph-backed) for agentic workflows -- `AgentExecutor` is legacy. All `@langchain/*` packages must share the same `@langchain/core` version or you get cryptic type errors at runtime. --- <critical_requirements> ## CRITICAL: Before Using This Skill > **All code must follow project conventions in CLAUDE.md** (kebab-case, named exports, import ordering, `import type`, named constants) **(You MUST use LCEL pipe composition (`prompt.pipe(model).pipe(parser)`) for all chains -- never use legacy `LLMChain`, `ConversationChain`, or `SequentialChain`)** **(You MUST ensure all `@langchain/*` packages depend on the same version of `@langchain/core` -- version mismatches cause cryptic runtime errors)** **(You MUST use `withStructuredOutput(zodSchema)` for structured LLM responses -- never manually parse JSON from completion text)** **(You MUST use `createAgent()` from `langchain` for new agent code -- `AgentExecutor` and `createToolCallingAgent` are legacy patterns)** **(You MUST never hardcode API keys -- use environment variables (`OPENAI_API_KEY`, `ANTHROPIC_API_KEY`, etc.))** </critical_requirements> --- **Auto-detection:** LangChain, langchain, @langchain/core, @langchain/openai, @la...