Use case

AI tools for developers — pair-programming for any language.

Def Code is a repo-aware AI CLI with Plan, Build, Design, and Test modes. Open-source Python SDK, MCP server, and a unified REST + streaming API across 50+ models. Works in any language; first-class TS/Python/Go/Rust/Swift/Kotlin.

Try Definable free See pricing

The problem

AI coding tools are siloed. Cursor only edits in its own editor. ChatGPT loses your repo context between messages. Most agents are demos that fall apart on a real codebase. And nobody gives developers a programmable API for the AI capabilities they actually need.

How Definable solves it

Def Code is a CLI you can pipe anywhere — terminal, CI, scripts. It reads your repo, respects your toolchain, runs your tests. Four modes for four stages of work: Plan (scope before coding), Build (reviewable diffs), Design (UI scaffolding from a brief), Test (coverage for legacy code).

Underneath, Definable exposes everything as APIs. Unified REST + streaming across 50+ models. Open-source Python SDK for building agents and tools. MCP server so Definable's integrations and knowledge bases become tools for any MCP-compatible client — Claude Desktop, Cursor, Windsurf, custom agents.

Bring-your-own keys (OpenAI, Anthropic, Google, Cohere, Together, Groq, Azure OpenAI, AWS Bedrock) on Pro and above. Air-gapped and VPC deployments on Enterprise.

How to ai tools for developers — pair-programming for any language

  1. 1

    Install Def Code

    Single binary or npm install. Works on macOS, Linux, Windows.

  2. 2

    Point it at a repo

    Def Code indexes your codebase and respects your toolchain.

  3. 3

    Pick a mode and a prompt

    Plan for design decisions, Build for diffs, Design for UI, Test for coverage.

  4. 4

    Review and ship

    Output is reviewable diffs and PR-ready commits. Your toolchain stays your toolchain.

Tools used

Def Code (CLI) →Compare to Cursor →

Frequently asked questions

What languages does Def Code support?

Any language your repo uses. First-class support for TypeScript, Python, Go, Rust, Swift, Kotlin. Working support for Ruby, Java, C#, PHP, C/C++, shell.

Can I use my own API keys?

Yes on Pro and above — bring your own OpenAI, Anthropic, Google, Cohere, Together, Groq, Azure OpenAI, or AWS Bedrock keys.

Is there an MCP server?

Yes. Definable exposes its integrations and knowledge bases as MCP tools, consumable from Claude Desktop, Cursor, Windsurf, or any MCP client.

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