--- title: HAR: Open Source harness for multi-agent coding workflows description: HAR is an open-source, agent-agnostic CLI and MCP server framework for running multi-agent coding workflows at scale. It solves key problems in parallel agent... canonical: https://daily.dev/posts/har-open-source-harness-for-multi-agent-coding-workflows-cnz7hfq15 twitter:card: summary_large_image twitter:site: @dailydotdev og:type: website og:site_name: daily.dev og:title: HAR: Open Source harness for multi-agent coding workflows | daily.dev og:description: HAR is an open-source, agent-agnostic CLI and MCP server framework for running multi-agent coding workflows at scale. It solves key problems in parallel agent... og:url: https://daily.dev/posts/har-open-source-harness-for-multi-agent-coding-workflows-cnz7hfq15 og:image: https://api.daily.dev/og/posts/cNZ7HfQ15.png og:image:alt: HAR: Open Source harness for multi-agent coding workflows og:image:width: 1200 og:image:height: 630 og:locale: en --- > ## Documentation Index > Fetch the complete documentation index at: https://daily.dev/llms.txt > Use this file to discover all available pages before exploring further. # HAR: Open Source harness for multi-agent coding workflows **[Product Hunt](https://daily.dev/sources/ph)** · 1 min read · 14 upvotes · 1 comments ## Summary HAR is an open-source, agent-agnostic CLI and MCP server framework for running multi-agent coding workflows at scale. It solves key problems in parallel agent execution: isolation via per-agent git worktrees, branches, ports, and databases; deterministic validation gates that bind results to exact code; verifiable proof artifacts for reviewers; and a local Mission Control dashboard for full fleet observability. It works with Claude Code, Cursor, Codex, and any MCP-compatible agent, replacing scattered README/CLAUDE.md/CI configs with a single committed contract. ## Full article daily.dev links to this article rather than hosting it. Read it at the original source: ## Questions this post answers ### How can I run multiple AI coding agents like Claude Code or Cursor in parallel on the same repository without them colliding? Use a harness like HAR, an open-source CLI and MCP server that gives each agent its own isolated git worktree, branch, ports, and database. This prevents agents from conflicting on a shared dev server, database, or git state, letting a fleet of agents work simultaneously while a fixed validation pipeline and commit-time checks ensure only verified changes land. _Developers scaling parallel AI coding agents can follow tools like this via daily.dev to avoid workflow collisions._ ## Community discussion Top comments from developers on daily.dev. **@pdfopsdev** · 0 upvotes > how's it handling port collisions when you scale past like 6-8 parallel worktrees? that's the part that always breaks for me when I try to run agents concurrently, not the git isolation. ## Similar posts on daily.dev - [What Is an Agent Harness? The Architecture Behind Claude Code, DeepSeek Harness, and Hermes Agent](https://daily.dev/posts/what-is-an-agent-harness-the-architecture-behind-claude-code-deepseek-harness-and-hermes-agent-yewiwnntj) · freeCodeCamp · 12 upvotes · 1 comments - [Harness Launches Autonomous Worker Agents for Software Delivery](https://daily.dev/posts/harness-launches-autonomous-worker-agents-for-software-delivery-gb2ydwalv) · SD Times · 3 upvotes · 0 comments - [Run Any Agent Harness Under One Interface](https://daily.dev/posts/run-any-agent-harness-under-one-interface-01asd0jn4) · Daily Dose of Data Science \| Avi Chawla \| Substack · 3 upvotes · 1 comments --- Tags: [#ai-agents](https://daily.dev/tags/ai-agents), [#automation](https://daily.dev/tags/automation), [#observability](https://daily.dev/tags/observability), [#mcp](https://daily.dev/tags/mcp) [View this post on daily.dev](https://daily.dev/posts/har-open-source-harness-for-multi-agent-coding-workflows-cnz7hfq15) ```json {"@context":"https://schema.org","@graph":[{"@type":"Organization","@id":"https://daily.dev/#organization","name":"daily.dev","url":"https://daily.dev","logo":{"@type":"ImageObject","url":"https://daily.dev/apple-touch-icon.png","width":180,"height":180},"sameAs":["https://twitter.com/dailydotdev","https://github.com/dailydotdev","https://www.linkedin.com/company/daily-dev-ltd"]},{"@type":"WebSite","@id":"https://daily.dev/#website","url":"https://daily.dev","name":"daily.dev","publisher":{"@id":"https://daily.dev/#organization"},"potentialAction":{"@type":"SearchAction","target":{"@type":"EntryPoint","urlTemplate":"https://daily.dev/search?q={search_term_string}"},"query-input":"required name=search_term_string"}}]} {"@context":"https://schema.org","@type":"TechArticle","headline":"HAR: Open Source harness for multi-agent coding workflows","url":"https://daily.dev/posts/har-open-source-harness-for-multi-agent-coding-workflows-cnz7hfq15","mainEntityOfPage":{"@type":"WebPage","@id":"https://daily.dev/posts/har-open-source-harness-for-multi-agent-coding-workflows-cnz7hfq15"},"datePublished":"2026-08-07T07:50:10.529Z","dateModified":"2026-09-14T06:54:33.135Z","description":"HAR is an open-source, agent-agnostic CLI and MCP server framework for running multi-agent coding workflows at scale. 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