{"type":"post","id":"how-we-built-our-design-agent-48f162","slug":"how-we-built-our-design-agent-48f162","title":"How We Built Our Design Agent","description":"LangChain has open-sourced Content Studio, its internal Slack-based design agent, alongside an account of the harness and feedback process behind it.","retrieval_nugget":"LangChain has open-sourced Content Studio, its internal Slack-based design agent, alongside an account of the harness and feedback process behind it. The useful signal for AI builders is that on-brand output came from a persistent, tool-rich environment and encoded review judgment—not from asking a model for better designs.","published_at":"2026-10-27","updated_at":"2026-10-27","record_date":"2026-10-27","date_kind":"published_at","topics":["harness-engineering","agent-runtime"],"entities":["LangChain","Content Studio","Deep Agents","Managed Deep Agents","LangSmith Sandbox","Slack","Opus 5.5"],"related_patterns":["harness-architecture-outlives-model-choice","design-systems-become-agent-context"],"novelty_label":"new_fact","what_changed":"The announced design-agent walkthrough is now a detailed build account, adding its architecture, design principles, four-month development process, and open-source/Managed Deep Agents availability.","prior_refs":["memory:52369057-9689-83ee-a69f-9614166ef766","memory:d62eeb28-c42b-8df3-a9d6-4ec653aeab66"],"source_url":"https://www.langchain.com/blog/design-agent","source_urls":["https://www.langchain.com/blog/design-agent"],"schema_version":"newruntime-agent-readable-v0.2","stable_id":"post:how-we-built-our-design-agent-48f162","status":"published","visuals":[],"editor":{"role":"editor","name":"Andrey Reshetnikov","profile":"https://newruntime.com/owner-profile.md","profile_json":"https://newruntime.com/owner-profile.json","same_as":["https://www.linkedin.com/in/reshetnikov1/","https://t.me/lapetuse"]},"routes":{"html":"https://newruntime.com/posts/how-we-built-our-design-agent-48f162/","markdown":"https://newruntime.com/posts/how-we-built-our-design-agent-48f162.md","json":"https://newruntime.com/posts/how-we-built-our-design-agent-48f162.json"},"next_reads":[{"type":"topic","path":"/topics/harness-engineering/","url":"https://newruntime.com/topics/harness-engineering/","title":"Harness Engineering","reason":"Explore the harness-engineering topic hub.","media_type":"text/html","markdown_url":"https://newruntime.com/topics/harness-engineering.md","json_url":"https://newruntime.com/topics/harness-engineering.json"},{"type":"topic","path":"/topics/agent-runtime/","url":"https://newruntime.com/topics/agent-runtime/","title":"Agent Runtime","reason":"Explore the agent-runtime topic hub.","media_type":"text/html","markdown_url":"https://newruntime.com/topics/agent-runtime.md","json_url":"https://newruntime.com/topics/agent-runtime.json"},{"type":"collection","path":"/posts/","url":"https://newruntime.com/posts/","title":"Field Notes","reason":"Open the latest editorial analysis.","media_type":"text/html","json_url":"https://newruntime.com/posts.json"},{"type":"collection","path":"/source-ledger.json","url":"https://newruntime.com/source-ledger.json","title":"Source Ledger","reason":"Inspect the public source evidence graph.","media_type":"application/json"}]}