# Send LangChain to your agent Hand the extracted package to your coding agent with a concrete install brief instead of figuring it out manually. ## Fast path - Download the package from Yavira. - Extract it into a folder your agent can access. - Paste one of the prompts below and point your agent at the extracted folder. ## Suggested prompts ### New install ```text I downloaded a skill package from Yavira. Read SKILL.md from the extracted folder and install it by following the included instructions. Tell me what you changed and call out any manual steps you could not complete. ``` ### Upgrade existing ```text I downloaded an updated skill package from Yavira. Read SKILL.md from the extracted folder, compare it with my current installation, and upgrade it while preserving any custom configuration unless the package docs explicitly say otherwise. Summarize what changed and any follow-up checks I should run. ``` ## Machine-readable fields ```json { "schemaVersion": "1.0", "item": { "slug": "langchain", "name": "LangChain", "source": "tencent", "type": "skill", "category": "AI 智能", "sourceUrl": "https://clawhub.ai/ivangdavila/langchain", "canonicalUrl": "https://clawhub.ai/ivangdavila/langchain", "targetPlatform": "OpenClaw" }, "install": { "downloadUrl": "/downloads/langchain", "sourceDownloadUrl": "https://wry-manatee-359.convex.site/api/v1/download?slug=langchain", "sourcePlatform": "tencent", "targetPlatform": "OpenClaw", "packageFormat": "ZIP package", "primaryDoc": "SKILL.md", "includedAssets": [ "SKILL.md" ], "downloadMode": "redirect", "sourceHealth": { "source": "tencent", "slug": "langchain", "status": "healthy", "reason": "direct_download_ok", "recommendedAction": "download", "checkedAt": "2026-05-02T04:37:42.418Z", "expiresAt": "2026-05-09T04:37:42.418Z", "httpStatus": 200, "finalUrl": "https://wry-manatee-359.convex.site/api/v1/download?slug=langchain", "contentType": "application/zip", "probeMethod": "head", "details": { "probeUrl": "https://wry-manatee-359.convex.site/api/v1/download?slug=langchain", "contentDisposition": "attachment; filename=\"langchain-1.0.0.zip\"", "redirectLocation": null, "bodySnippet": null, "slug": "langchain" }, "scope": "item", "summary": "Item download looks usable.", "detail": "Yavira can redirect you to the upstream package for this item.", "primaryActionLabel": "Download for OpenClaw", "primaryActionHref": "/downloads/langchain" }, "validation": { "installChecklist": [ "Use the Yavira download entry.", "Review SKILL.md after the package is downloaded.", "Confirm the extracted package contains the expected setup assets." ], "postInstallChecks": [ "Confirm the extracted package includes the expected docs or setup files.", "Validate the skill or prompts are available in your target agent workspace.", "Capture any manual follow-up steps the agent could not complete." ] } }, "links": { "detailUrl": "https://openagent3.xyz/skills/langchain", "downloadUrl": "https://openagent3.xyz/downloads/langchain", "agentUrl": "https://openagent3.xyz/skills/langchain/agent", "manifestUrl": "https://openagent3.xyz/skills/langchain/agent.json", "briefUrl": "https://openagent3.xyz/skills/langchain/agent.md" } } ``` ## Documentation ### LCEL Basics | pipes output to next — prompt | llm | parser RunnablePassthrough() forwards input unchanged — use in parallel branches RunnableParallel runs branches concurrently — {"a": chain1, "b": chain2} .invoke() for single, .batch() for multiple, .stream() for tokens Input must match expected keys — {"question": x} not just x if prompt expects {question} ### Memory Gotchas Memory doesn't auto-persist between sessions — save/load explicitly ConversationBufferMemory grows unbounded — use ConversationSummaryMemory for long chats Memory key must match prompt variable — memory_key="chat_history" needs {chat_history} in prompt return_messages=True for chat models — False returns string for completion models ### RAG Chunking Chunk size affects retrieval quality — too small loses context, too large dilutes relevance Chunk overlap prevents cutting mid-sentence — 10-20% overlap typical RecursiveCharacterTextSplitter preserves structure — splits on paragraphs, then sentences Embedding dimension must match vector store — mixing models causes silent failures ### Output Parsers PydanticOutputParser needs format instructions in prompt — call .get_format_instructions() Parser failures aren't always loud — malformed JSON may partially parse OutputFixingParser retries with LLM — wraps another parser, fixes errors with_structured_output() on chat models — cleaner than manual parsing for supported models ### Retrieval similarity_search returns documents — .page_content for text k parameter controls results count — more isn't always better, noise increases Metadata filtering before similarity — filter={"source": "docs"} in most vector stores max_marginal_relevance_search for diversity — avoids redundant similar chunks ### Agents Agents decide tool order dynamically — chains are fixed sequence Tool descriptions matter — agent uses them to decide when to call handle_parsing_errors=True — prevents crash on malformed agent output Max iterations prevents infinite loops — max_iterations=10 default may be too low ### Common Mistakes Prompt template variables case-sensitive — {Question} ≠ {question} Chat models need message format — ChatPromptTemplate, not PromptTemplate Callbacks not propagating — pass config={"callbacks": [...]} through chain Rate limits crash silently sometimes — wrap in retry logic Token count exceeds context — use trim_messages or summarization for long histories ## Trust - Source: tencent - Verification: Indexed source record - Publisher: ivangdavila - Version: 1.0.0 ## Source health - Status: healthy - Item download looks usable. - Yavira can redirect you to the upstream package for this item. - Health scope: item - Reason: direct_download_ok - Checked at: 2026-05-02T04:37:42.418Z - Expires at: 2026-05-09T04:37:42.418Z - Recommended action: Download for OpenClaw ## Links - [Detail page](https://openagent3.xyz/skills/langchain) - [Send to Agent page](https://openagent3.xyz/skills/langchain/agent) - [JSON manifest](https://openagent3.xyz/skills/langchain/agent.json) - [Markdown brief](https://openagent3.xyz/skills/langchain/agent.md) - [Download page](https://openagent3.xyz/downloads/langchain)