OpenSpec

OpenSpec

Fission AI
+
+

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About

OpenSpec is an open-source spec-driven development framework designed to bring structure and clarity to AI-assisted coding workflows. It introduces a lightweight specification layer that helps teams define requirements before writing code. The platform organizes each change into structured artifacts such as proposals, specifications, designs, and task lists. It integrates with over 20 AI coding tools, allowing developers to use their preferred assistants while maintaining consistency. OpenSpec emphasizes an iterative and flexible approach rather than rigid development phases. Its command-based workflow enables users to propose, implement, and archive features efficiently. Overall, OpenSpec helps developers align with AI systems, reduce ambiguity, and produce more predictable and reliable outcomes.

About

Tessl’s AI native development platform delivers secure, high-quality, and auto-maintained code, all built to your specs. Tessl’s approach to spec-driven development, grounded in rigorous, deterministic conformance tests, lets you define the requirements, while AI generates the code. Tessl’s platform is a new approach to building software. One built from the ground up with AI in mind. Software built with Tessl is composed using small, modular units that combine to form complex systems. Tessl is created to work with today’s LLMs while anticipating tomorrow’s AI innovations. With Tessl, quality control is built in, via spec conformance tests and platform-wide code quality evaluations. Push the boundaries of generative AI in an environment designed to let you tinker and explore. Experiment with workflows, models, prompts, and more. Tessl enables easier collaboration based on specs, and our high-quality, auto-generated documentation makes code easier than ever to consume.

Platforms Supported

Windows Supported
Mac Supported
Linux Supported
Cloud Not Supported
On-Premises Supported
iPhone Not Supported
iPad Not Supported
Android Not Supported
Chromebook Not Supported

Platforms Supported

Windows Not Supported
Mac Not Supported
Linux Not Supported
Cloud Supported
On-Premises Not Supported
iPhone Not Supported
iPad Not Supported
Android Not Supported
Chromebook Not Supported

Audience

Developers, product teams, and organizations using AI coding assistants who want a structured, spec-driven approach to improve clarity, collaboration, and development outcomes

Audience

Developers looking for a solution to manage and evaluate their code's quality

Support

Phone Support Not Supported
24/7 Live Support Not Supported
Online Not Supported

Support

Phone Support Not Supported
24/7 Live Support Not Supported
Online Supported

API

Offers API Not Supported

API

Offers API Supported

Screenshots and Videos

Screenshots and Videos

Pricing

Free
Open source
Free Version Supported
Free Trial Not Supported

Pricing

No information available.
Free Version Not Supported
Free Trial Not Supported

Reviews/Ratings

Overall 0.0 / 5
ease 0.0 / 5
features 0.0 / 5
design 0.0 / 5
support 0.0 / 5

This software hasn't been reviewed yet. Be the first to provide a review:

Review this Software

Reviews/Ratings

Overall 0.0 / 5
ease 0.0 / 5
features 0.0 / 5
design 0.0 / 5
support 0.0 / 5

This software hasn't been reviewed yet. Be the first to provide a review:

Review this Software

Training

Documentation Supported
Webinars Not Supported
Live Online Not Supported
In Person Not Supported

Training

Documentation Supported
Webinars Not Supported
Live Online Not Supported
In Person Supported

Company Information

Fission AI
openspec.dev/

Company Information

Tessl
Founded: 2024
United Kingdom
www.tessl.io

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Categories

Agentic AI Supported
AI Coding Agents Supported

Categories

AI Code Generators Supported
Code Quality Supported

Integrations

Claude Code Supported
Claude Haiku 3 Not Supported
Claude Opus 3 Not Supported
Claude Sonnet 3.7 Not Supported
Cline Supported
CoStrict Supported
Codebuddy Supported
Factory Supported
GPT-4o mini Not Supported
Gemini Not Supported
Gemini 1.5 Pro Not Supported
Gemini 2.0 Not Supported
Gemini 2.0 Flash Not Supported
Gemini Nano Not Supported
Gemini Pro Not Supported
GitHub Copilot Supported
JSON Not Supported
OpenCode Supported
Qwen Code Supported
XML Not Supported

Integrations

Claude Code Not Supported
Claude Haiku 3 Supported
Claude Opus 3 Supported
Claude Sonnet 3.7 Supported
Cline Not Supported
CoStrict Not Supported
Codebuddy Not Supported
Factory Not Supported
GPT-4o mini Supported
Gemini Supported
Gemini 1.5 Pro Supported
Gemini 2.0 Supported
Gemini 2.0 Flash Supported
Gemini Nano Supported
Gemini Pro Supported
GitHub Copilot Not Supported
JSON Supported
OpenCode Not Supported
Qwen Code Not Supported
XML Supported
Claim OpenSpec and update features and information
Claim OpenSpec and update features and information
Claim Tessl and update features and information
Claim Tessl and update features and information