Why it mattersA shared spec workflow across 40 coding assistants means a team can move between agents without rewriting how they capture what to build, which lowers the switching cost that today locks a project to one vendor.
OpenSpec, an MIT-licensed spec framework by Fission-AI, reached 68,579 GitHub stars this week and cut a v1.13.1 release on 17 September, hours before a Hacker News thread on the project reached 72 points. The tool sits between a developer and any of a long list of AI coding assistants, and asks them to work from a written specification instead of a plain chat prompt.
The pitch is spec-driven development for AI coding. A developer runs five commands in the assistant of their choice: /opsx:explore maps the problem and the codebase, /opsx:propose drafts a proposal, the specs, a design and a task list, /opsx:apply implements the tasks, /opsx:verify checks the code against the spec, and /opsx:archive closes out the change. The spec, not the chat history, becomes the record of what the team asked for.
The vendor-neutral part is what is new
OpenSpec's own compatibility page lists Claude Code, Codex, Cursor, GitHub Copilot, Gemini CLI and OpenCode as the primary targets, then a further list of Amazon Q Developer, Antigravity, Auggie, IBM Bob Shell, Cline, CodeArts, CodeBuddy, Devin Desktop, ForgeCode, Continue, CoStrict, Crush, Factory Droid, Hermes Agent, iFlow, Junie, Kilo Code, Kimi Code, Kiro, Lingma, MiniMax Code, Mistral Vibe, Oh My Pi, Pi, SourceCraft, Qoder, Qwen Code, Rovo Dev CLI, Zoo Code, Trae, Zed Agent and ZCode. The site's tally is 39 tools with more in a full directory, so a project moving from one assistant to another does not have to rebuild the workflow around the new tool.
The Fission-AI GitHub repository was opened on 5 August 2025 and had 68,579 stars and 4,717 forks when checked on 17 September. The site also claims a new spec is created "every two seconds", which is a self-reported figure with no method attached, so treat it as a marketing statement rather than a measurement.
What changed in v1.13.1
The release notes call out security hardening as the headline change. A config.yaml value can no longer inject directives into agent instructions, a crafted file can no longer hang openspec update or openspec archive, and a repository's .npmrc can no longer redirect the update check. That matters because OpenSpec is often the first thing an AI assistant reads in a repository it has never seen, and each of those was a way for a hostile repository to steer the assistant.
The release also adds a Next: line to openspec status, so resuming a paused change no longer requires the developer to remember the five-step workflow by name. Explore and update workflows were tightened so /opsx:update drafts revisions first and writes only after confirmation, which is a plain fix for an assistant that used to overwrite specs without asking.
For a team already committed to one AI coding assistant, OpenSpec is a way to make the assistant's output easier to review: the spec is what a human reads and signs off on, and the code is checked against it after the fact. For a team that changes assistants, it is a way to keep the workflow when the tool underneath swaps.
Source
OpenSpec at openspec.dev and the Fission-AI/OpenSpec repository. Release notes for v1.13.1. Hacker News discussion thread.
Source: OpenSpec
This item was written by an AI system from the linked source. Reveneau is responsible for what it publishes.
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