Show HN: One Code, almost all of Claude Code's features on pi, with any model

An independent open-source project called One Code recreates Claude Code's coding workflow on top of pi while letting users plug in any model or provider, released free under the MIT license as the npm package @one-ai/one-code. One Code carries over subagents, Git worktrees, auto mode, plan mode, permissions and context management in the harness, and reads existing CLAUDE.md and .claude/ configuration directly with no import step, falling back to AGENTS.md when no CLAUDE.md exists. It requires Node.js 22.19 or later, supports Anthropic, OpenAI, Gemini, OpenRouter or local models with mid-session switching via /model, and is developed and verified on macOS, Linux and Windows; features depending on Claude Code's hosted or desktop services are outside its scope.

Claude Code with the model slot left open. The full workflow, open source, on any model or provider. One Code rebuilds the Claude Code workflow around the model you choose. Subagents, Git worktrees, auto mode, plan mode, permissions, and context management all live in the harness, so they come along whatever model you put in it. Your CLAUDE.md , skills, commands, agents, and permission rules carry over with no import step. If you already use Claude Code, nothing here needs relearning. Pick a model, give it a task, review its plan, and let it work. Switch models mid-session, or give each subagent its own model and provider: a frontier model on the main task, a cheaper one for exploration and tests. One Code is an independent, open-source implementation built on pi https://github.com/earendil-works/pi . It recreates the coding workflow; features that depend on Claude Code's hosted or desktop services are outside its scope. User guide https://github.com/IsuruMaduranga/one-code/blob/master/docs/guide/README.md · Reuse your Claude Code setup https://github.com/IsuruMaduranga/one-code/blob/master/docs/guide/bring-your-claude-code-setup.md · Differences from Claude Code https://github.com/IsuruMaduranga/one-code/blob/master/docs/guide/differences-from-claude-code.md · Command reference https://github.com/IsuruMaduranga/one-code/blob/master/docs/guide/reference.md Install Node.js 22.19 or later , then run: npm install -g @one-ai/one-code cd your-project onecode Inside One Code, run /login to connect a provider, then /model to choose a model. You can also supply an API key through an environment variable such as ANTHROPIC API KEY , OPENAI API KEY , or OPENROUTER API KEY . One Code reads an existing CLAUDE.md and .claude/ configuration directly. If a directory has no CLAUDE.md , it falls back to AGENTS.md . For a new project, run /init to draft a CLAUDE.md . To check your setup, run onecode doctor or /doctor report inside a session. The report lists provider credentials, model assignments, detected configuration, and missing programs. Run /doctor for a checkup with agent-assisted fixes. One Code is developed on macOS and verified on macOS, Linux, and Windows. WSL works too. For the native Windows setup and what has been checked there, see the Windows guide https://github.com/IsuruMaduranga/one-code/blob/master/docs/guide/windows.md . One Code is free under the MIT license. Model access, usage charges, and rate limits depend on your provider. See Providers and models https://github.com/IsuruMaduranga/one-code/blob/master/docs/guide/providers-and-models.md for connection options. Homebrew , which installs Node.js for you: brew install isurumaduranga/one-ai/onecode Windows installer , which installs Node.js and One Code: powershell -c "irm https://raw.githubusercontent.com/IsuruMaduranga/one-code/master/install.ps1 | iex" Existing pi installation : pi install npm:one-code-extension The @one-ai/one-code https://www.npmjs.com/package/@one-ai/one-code app package bundles a pinned version of pi and provides the onecode command. The one-code-extension https://www.npmjs.com/package/one-code-extension package uses your existing pi installation and is tested against pi versions 1.0.0 through 1.5. For the extension package, use pi in place of onecode . The app opens in a full-screen terminal interface by default. See the installation guide https://github.com/IsuruMaduranga/one-code/blob/master/docs/guide/installation.md for display settings and more installation details. - Choose models by task. Use Anthropic, OpenAI, Gemini, OpenRouter, or a local model. Switch the main model mid-session with /model . - Mix providers in one session. Give the main agent and each subagent their own model and provider, without configuring a routing gateway. - Reuse your Claude Code configuration. One Code reads project instructions, skills, commands, agents, plugins, permission rules, and Model Context Protocol MCP server configuration. There is no import step. - Adapt guidance to the model. Four capability tiers adjust prompting and tool guidance, with more explicit instructions for smaller models. - Extend the harness. One Code is a pi https://github.com/earendil-works/pi package built from extensions. Add your own extensions, themes, and settings. - Inspect and change the code. The project is open source under the MIT license https://github.com/IsuruMaduranga/one-code/blob/master/LICENSE . You can point Claude Code at another endpoint with ANTHROPIC BASE URL . If that endpoint supports the API Claude Code expects, this can be enough to use an alternative model in a familiar interface. The override changes where requests go. It does not, by itself, adapt the prompts, provider features, authentication, or supporting model calls to the model receiving them. Your endpoint or gateway has to bridge those gaps. One Code builds that adaptation into the harness: - Different providers for different agents. A URL override points requests at one endpoint. To route those requests across providers, you need a gateway. One Code connects each agent to its own provider directly. The main agent can use a frontier model while subagents use a cheaper model elsewhere. - Prompts matched to the model. Changing the endpoint does not change the instructions sent to the model. One Code uses four capability tiers to adjust prompting and tool guidance. Smaller and local models receive more explicit playbooks and structured search tools. - Native caching support. Providers use different caching mechanisms. An API-compatible response alone does not establish that a gateway preserves caching behavior. One Code uses native provider integrations, keeps prompt prefixes stable, and shows the cache hit rate in the footer. - Account sign-ins as well as API keys. Changing a URL does not add a provider's sign-in flow. One Code signs in with the accounts you already have Claude Pro and Max, ChatGPT, GitHub Copilot, OpenRouter, Kimi, xAI, and Radius , and you can mix them with API-key connections in the same session. - Tools and supporting calls that account for the provider. Web search, deferred tools, reasoning, and background model calls need more than an endpoint change. One Code provides shared tool interfaces and selects supporting models from the provider's catalog, subject to capability requirements. - Auto mode on any provider. Claude Code's auto mode now sends each tool call to the API server for a safety check, using a request field the endpoint has to support. Claude Code keeps its local classifier as a fallback only for a while LiteLLM's notes https://docs.litellm.ai/blog/claude-code-server-side-auto-mode give October 23, 2026 , so an endpoint without that support can leave auto mode unavailable. One Code runs its own two-stage classifier on a model from your provider, so auto mode works wherever your models run. - An open harness you can change. One Code's prompts, tools, and workflows are implemented as pi extensions. You can inspect them, change their behavior, and add your own. Use a URL override when one compatible endpoint covers your needs. Use One Code when you want the Claude Code workflow with model choice built into the prompts, tools, authentication, and agent coordination. See Differences from Claude Code https://github.com/IsuruMaduranga/one-code/blob/master/docs/guide/differences-from-claude-code.md for the full comparison and compatibility boundaries. Keep your preferred model on the main task and delegate exploration, tests, or review to another model or provider. 1. Choose the main model with /model . 2. Set the default model for subagents and workflow agents with /subagent <provider/model-id . 3. Ask for delegated work. For example: Use subagents to investigate the authentication code and its tests. Have them report their findings, then make the fix in the main session. Agent definitions in .claude/agents/ can specify their own model, tools, and instructions. Use /agents to follow their progress and /model to change the main model as the task changes. Cost and output quality depend on the models, the task, and how much work you delegate. See Subagents and workflows https://github.com/IsuruMaduranga/one-code/blob/master/docs/guide/subagents-and-workflows.md for configuration details. One Code reads Claude Code configuration directly and keeps its own settings separately. It treats ~/.claude as read-only, with one deliberate exception: per-repository memory is written to Claude Code's own memory folder, so both tools share it. | Configuration | How One Code uses it | |---|---| | CLAUDE.md | Project instructions, including nested files and @path imports. Falls back to AGENTS.md when a directory has no CLAUDE.md . | | .claude/skills/ and .claude/commands/ | Discoverable skills and slash commands. | | .claude/agents/ | Subagent definitions with model, tool, and instruction settings. | | .claude/settings.json | allow , deny , and ask permission rules, plus supported command hooks. | | .mcp.json | MCP servers, with tools loaded on demand. | | Installed Claude Code plugins | Plugin agents, skills, commands, and MCP servers, namespaced by plugin. | Claude Code tool names such as Read , Bash , Edit , and Task work in permission rules and hook matchers. Compatibility covers configuration and workflows. Features and skills that depend on Claude Code's hosted or desktop services are not included. See Configuration compatibility https://github.com/IsuruMaduranga/one-code/blob/master/docs/guide/bring-your-claude-code-setup.md and Skills, plugins, and MCP https://github.com/IsuruMaduranga/one-code/blob/master/docs/guide/skills-plugins-and-mcp.md . Give an investigation its own context window and bring the results back to the main conversation. Subagents run in the background, accept follow-up messages, and can fork the conversation when they need its context. One Code includes three agent definitions: general-purpose , explore , and plan . For parallel edits, give agents separate Git worktrees. You can also move the whole session into a worktree with enter worktree and leave it with exit worktree . Include ultracode in a request for a broad audit, migration, or review. The model writes a JavaScript workflow to coordinate agents in parallel. Follow progress in /workflows , or use /effort ultracode to keep this behavior enabled across turns. When you resume an interrupted run, completed agent calls can be reused if their inputs still match. Save reusable scripts in .claude/workflows/ to call them by name. Optional output-token targets stop new and queued agents when the target is reached. Agents already running can finish above the target. Auto mode is the default. A classifier evaluates actions that need review, while permission rules and deterministic checks enforce the remaining controls. deny rules take precedence over allow rules. Project-provided hooks, MCP servers, and allow rules require trust approval. Press ctrl+q , or alt+m on Windows and WSL, to cycle through manual, accept-edits, plan, and auto modes. In plan mode, the agent investigates and writes a plan file before you approve implementation. Use /permissions to manage rules and approve calls auto mode blocked, and /auto-mode to configure the classifier. The permission system provides application-level controls. For operating system isolation, run One Code inside a container. See Permissions and modes https://github.com/IsuruMaduranga/one-code/blob/master/docs/guide/permissions-modes-and-auto-mode.md for guarantees and known limitations, and Hooks https://github.com/IsuruMaduranga/one-code/blob/master/docs/guide/hooks.md for hook configuration. | Capability | Included features | |---|---| | Code and files | File reading, writing, and editing; shell commands; background processes; repository search; and notebook editing. | | Web | Search and fetch, using provider search or Brave, Tavily, and Exa fallbacks. | | Diagnostics | Language server diagnostics after edits. Install the relevant server on your PATH . | | Long sessions | Per-repository memory, a session scratchpad, and context compaction. | | Task tracking | A pinned progress widget, background monitors, and scheduled wake-ups. | | Tool discovery | Tools loaded on demand to reduce prompt overhead. | | Artifacts | HTML pages the model writes reports, dashboards, small tools , saved in ~/.onecode/artifacts/ with every version kept, and opened in your browser. | | Reasoning and appearance | /effort or shift+tab to set reasoning effort; onecode and onecode-light themes. | | Customization | pi extensions, themes, and settings. | Bundled skills include simplify , code-review , security-review , fewer-permission-prompts , and artifact-design . A project skill with the same name takes precedence. For scripting and session management: onecode -p "Explain how authentication works in this repository" onecode -c Continue the previous session. onecode --mode json Output JSON events. onecode --permission-mode plan Start in plan mode. See Tools https://github.com/IsuruMaduranga/one-code/blob/master/docs/guide/tools.md for available tools and the command reference https://github.com/IsuruMaduranga/one-code/blob/master/docs/guide/reference.md for commands, shortcuts, flags, and environment variables. - Provider coverage: End-to-end testing focuses on Anthropic, OpenAI, and OpenRouter. Other providers have less test coverage. - Web search: For providers without native search, set BRAVE SEARCH API KEY or TAVILY API KEY . Without either key, One Code falls back to Exa's rate-limited keyless endpoint and labels those results. - Native Windows: The shells, hooks, and the PowerShell tool follow Claude Code's behavior. They pass on the Windows CI runner, where a real model drives both shell tools, and they have been checked by hand on a Windows Server 2025 machine: the interface in Windows Terminal, permission prompts, plan mode, the PowerShell tool, background shells, and /doctor . Windows 10 and 11 desktops have had less time in the field, so report what you hit. WSL remains the longest-tested route. To install the local extensions into an existing pi installation, run: git clone https://github.com/IsuruMaduranga/one-code cd one-code npm install cd .. pi install ./one-code pi list The user guide https://github.com/IsuruMaduranga/one-code/blob/master/docs/guide/README.md covers setup, configuration, providers, permissions, workflows, tools, session management, and troubleshooting. If you want to change One Code itself, the developer docs https://github.com/IsuruMaduranga/one-code/blob/master/docs/dev/README.md cover the architecture, the rules extensions follow, and how to test. For the ideas behind the project, read Harness Engineering 101 https://isuruwijesiri.com/harness-engineering-101/ . The sixteen-chapter series starts with a small coding agent and develops the harness patterns used in One Code, with examples from this repository. MIT https://github.com/IsuruMaduranga/one-code/blob/master/LICENSE . Contributions are welcome.