{"type":"post","id":"mainplane-is-a-new-open-source-mit-licensed-a73b75","slug":"mainplane-is-a-new-open-source-mit-licensed-a73b75","title":"Mainplane is a new open-source, MIT-licensed agent harness written in Go.","description":"Mainplane is an MIT-licensed, open-source agent harness with a self-hosting quickstart for running agents across computers, connectors, model providers, files, browsers, and applications.","retrieval_nugget":"Mainplane is an MIT-licensed, open-source agent harness with a self-hosting quickstart for running agents across computers, connectors, model providers, files, browsers, and applications. For teams building agentic workflows, it is another attempt to make the harness—not a single model chat—the operational layer where access, context, and execution are organized.","published_at":"2026-10-31","updated_at":"2026-10-31","record_date":"2026-10-31","date_kind":"published_at","topics":["agent-harness","claude","claude-code"],"entities":["Mainplane","mainplane-ai/mainplane","Anthropic","OpenAI","Google","Claude Code","ChatGPT Codex"],"related_patterns":["harness-architecture-outlives-model-choice","agent-security-moves-to-runtime-boundaries"],"novelty_label":"new_fact","what_changed":"Mainplane adds a distinct MIT-licensed agent harness written in Go to the archive’s coverage of open-source agent tools.","prior_refs":["memory:1d940e02-c1d7-81df-a69f-b86244fbd19b","memory:d003d0fc-b783-88b8-a8d9-bd96c30b57f4"],"source_url":"https://github.com/mainplane-ai/mainplane","source_urls":["https://github.com/mainplane-ai/mainplane"],"schema_version":"newruntime-agent-readable-v0.2","stable_id":"post:mainplane-is-a-new-open-source-mit-licensed-a73b75","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/mainplane-is-a-new-open-source-mit-licensed-a73b75/","markdown":"https://newruntime.com/posts/mainplane-is-a-new-open-source-mit-licensed-a73b75.md","json":"https://newruntime.com/posts/mainplane-is-a-new-open-source-mit-licensed-a73b75.json"},"next_reads":[{"type":"topic","path":"/topics/agent-harness/","url":"https://newruntime.com/topics/agent-harness/","title":"Agent Harness","reason":"Explore the agent-harness topic hub.","media_type":"text/html","markdown_url":"https://newruntime.com/topics/agent-harness.md","json_url":"https://newruntime.com/topics/agent-harness.json"},{"type":"topic","path":"/topics/claude/","url":"https://newruntime.com/topics/claude/","title":"Claude","reason":"Explore the claude topic hub.","media_type":"text/html","markdown_url":"https://newruntime.com/topics/claude.md","json_url":"https://newruntime.com/topics/claude.json"},{"type":"topic","path":"/topics/claude-code/","url":"https://newruntime.com/topics/claude-code/","title":"Claude Code","reason":"Explore the claude-code topic hub.","media_type":"text/html","markdown_url":"https://newruntime.com/topics/claude-code.md","json_url":"https://newruntime.com/topics/claude-code.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"}]}