Reasonix is a free, open-source AI coding agent that runs in your terminal or desktop app and uses the DeepSeek API for code editing, shell-assisted workflows, MCP tools, memory, skills, hooks, and long coding sessions.
Most AI coding agents treat the model’s prefix cache as an incidental property. Reasonix builds the entire session loop around DeepSeek’s byte-stable cache mechanic.
A real-world case study shows 435 million input tokens processed in a single day at a 99.82% cache hit rate, with total cost at roughly $12 compared to an estimated $61 for the same workload without cache optimization.
That ratio matters in multi-hour coding sessions, where context grows large, and round trips accumulate fast.
Features
- Runs as a terminal AI coding agent or a desktop app.
- Supports reviewable SEARCH/REPLACE edits before files change.
- Gates shell commands through approval and workspace permissions.
- Connects MCP servers through stdio, SSE, and Streamable HTTP.
- Supports project and global skills through Markdown playbooks.
- Stores memory across global and project scopes.
- Supports hooks on lifecycle events such as tool use, prompt submit, and session stop.
- Includes configurable web search through Mojeek, SearXNG, or Metaso.
- Builds a semantic index through local Ollama embeddings or OpenAI-compatible embedding endpoints.
- Supports macOS, Linux, and Windows terminal workflows.
Reasonix vs Claude Code
Reasonix and Claude Code are both CLI-based AI agents that inspect a codebase, edit files, run commands, and help with development tasks from a coding workflow. The real difference is the model stack, cost profile, extension surface, and product maturity.
Choose Claude Code when you want the strongest mainstream coding-agent experience, official Anthropic model access, IDE support, cloud surfaces, and a mature product ecosystem.
Choose Reasonix when you already want to use DeepSeek, prefer an open-source terminal agent, and care more about long-session API cost control than a polished cross-platform product.
| Reasonix | Claude Code | |
|---|---|---|
| Model backend | DeepSeek only. | Claude models through Anthropic or supported providers. |
| License | MIT open source. | Proprietary product. |
| Cost model | Requires a DeepSeek API key. Long sessions can benefit from prefix-cache behavior. | Requires Claude subscription, Claude Console access, or supported cloud-provider access. |
| Best fit | Developers who want DeepSeek-first terminal coding with open-source control. | Developers who want the strongest Claude-based coding workflow across more surfaces. |
| Setup path | Install through npm or run with npx. | Install through native installer, Homebrew, WinGet, or supported platform flows. |
| Primary interface | Terminal CLI and Desktop | Terminal CLI, web, desktop, VS Code, JetBrains, Slack, and CI/CD surfaces. |
| File editing | Uses SEARCH/REPLACE review and /apply before changes hit disk. | Edits files directly with permission controls and review workflows. |
| Shell commands | Supports gated shell execution and workspace permissions. | Supports command execution with permissions and safety controls. |
| MCP support | Supports stdio, SSE, and Streamable HTTP MCP servers. | Supports MCP servers and broader official MCP workflows. |
| Skills | Supports Markdown skills, inline skills, and subagent skills. | Supports skills, custom commands, bundled skills, and plugin-based extension. |
| Memory | Supports project and global memory. | Uses CLAUDE.md, CLAUDE.local.md, auto memory, and project memory files. |
| Hooks | Supports PreToolUse, PostToolUse, UserPromptSubmit, and Stop hooks. | Supports lifecycle hooks, including session, prompt, tool-use, notification, and stop events. |
| Web search | Supports configurable search through Mojeek, SearXNG, or Metaso. | Supports search and related Claude Code workflows. |
| Local model support | No. Reasonix is DeepSeek-only. | No local-model-first workflow. Claude Code centers on Claude access. |
| Desktop app | Prerelease desktop client. | More mature official surface coverage. |
| Main limitation | DeepSeek-only backend and paid API usage. | Proprietary ecosystem and higher-cost premium model path. |
Reasonix is not a full Claude Code alternative for every developer. Claude Code remains the safer default when model quality, product maturity, IDE support, and official Anthropic workflows matter most.
Use Reasonix when these points match your workflow:
- You already use DeepSeek API for coding work.
- You want an open-source coding agent.
- You prefer terminal workflows over IDE-first assistants.
- You want reviewable SEARCH/REPLACE edits before file changes.
- You care about MCP, hooks, skills, and project memory.
- You want lower long-session cost as a core design goal.
Use Claude Code when these points matter more:
- You want the strongest Claude model experience.
- You need VS Code or JetBrains integration.
- You want official desktop, web, Slack, or CI/CD surfaces.
- You prefer a more mature product ecosystem.
- You want built-in Claude Code skills, plugins, and official workflows.
- You work on tasks where Claude’s reasoning quality matters more than DeepSeek API cost.
How to Use Reasonix
Install Reasonix globally when you want the reasonix command on your PATH.
npm install -g reasonixStart a coding session inside a project.
reasonix code my-projectRun Reasonix once through npx when you want to try the latest package without a global install.
cd my-project
npx reasonix codeUse the shorter dsnix alias when you prefer fewer keystrokes.
npm install -g dsnix
npx dsnix@latest codeRun Reasonix inside a different project folder.
npx reasonix code --dir /path/to/projectThe first run asks for a DeepSeek API key and stores it under the Reasonix config folder. Reasonix needs Node 22 or newer in the current project requirements, and it works on macOS, Linux, and Windows terminals.
Use reasonix doctor before serious project work to check Node, API key, and MCP wiring.
reasonix doctorUse reasonix update when you want to upgrade the CLI.
reasonix updateUse reasonix chat when you want conversation without filesystem and shell tools.
reasonix chatUse reasonix run for one-shot terminal output.
reasonix run "summarize this repository structure"Use /apply only after reviewing proposed SEARCH/REPLACE edits.
/applyUse /qq connect when you want QQ as a remote channel for the active session.
/qq connectFree Access and Limits
The coding agent is free and open source under the MIT license, but it requires a paid DeepSeek API key. The model usage cost depends on DeepSeek pricing, token volume, preset choice, and cache hit rate.
Reasonix is also not a multi-provider coding agent. Choose SmallCode, Pi Coding Agent or another local-model workflow when air-gapped use, Ollama-first usage, or provider switching matters more than DeepSeek-native cache behavior.
Quick Reference
Table Of Contents
Installation Commands
| Command | Purpose |
|---|---|
npm install -g reasonix | Install Reasonix globally. |
reasonix code my-project | Start code mode for a project path. |
cd my-project | Move into a project folder before running npx. |
npx reasonix code | Run the latest Reasonix package once. |
npm install -g dsnix | Install the shorter alias package. |
npx dsnix@latest code | Run Reasonix through the dsnix alias. |
reasonix | Launch code mode in the current directory. |
reasonix code [dir] | Launch the coding agent in a directory. |
reasonix code --help | Show flags for code mode. |
reasonix --help | Show available commands and subcommands. |
npx reasonix code --dir /path/to/project | Launch code mode with an explicit project root. |
Main CLI Commands
| Command | Purpose |
|---|---|
reasonix | Start the default code workflow. |
reasonix code [dir] | Start the coding agent. |
reasonix chat | Start plain chat with no filesystem or shell tools. |
reasonix run "task" | Run a one-shot task and stream output. |
reasonix doctor | Check Node, API key, and MCP wiring. |
reasonix update | Upgrade Reasonix. |
reasonix replay | Replay session data. |
reasonix diff | Inspect diffs. |
reasonix events | Inspect event data. |
reasonix stats | Inspect session or usage statistics. |
reasonix index | Build a semantic index. |
reasonix mcp | Manage MCP tooling. |
reasonix prune-sessions | Clean stored session data. |
Code Mode and Chat Mode
| Capability | code | chat |
|---|---|---|
| Filesystem tools | Yes | No |
edit_file | Yes | No |
| SEARCH/REPLACE review | Yes | No |
/apply | Yes | No |
| Gated shell tool | Yes | No |
| Plan mode | Yes | No |
/todo | Yes | No |
/skill new | Yes | No |
/mcp add | Yes | No |
remember and recall_memory | Project and global | Global only |
| MCP servers from config | Yes | Yes |
| Web search | Yes | Yes |
ask_choice | Yes | Yes |
| Coding system prompt | Yes | Generic |
| Session scope | Per directory | Shared default |
Slash Commands Mentioned
| Command | Purpose |
|---|---|
/apply | Apply reviewed SEARCH/REPLACE edits. |
/todo | Use plan or task tracking inside code mode. |
/skill new | Create a project skill. |
/skill new --global | Create a global skill. |
/skill list | List available skills. |
/skill show <name> | Print a skill body. |
/skill <name> [args] | Run a skill with optional arguments. |
/skill openspec-propose <task> | Run an OpenSpec skill workflow after setup. |
/mcp | Open the interactive MCP hub. |
/mcp add | Add MCP tooling inside code mode. |
/mcp disable <name> | Disable an MCP server on next launch. |
/mcp enable <name> | Re-enable a disabled MCP server. |
/mcp reconnect <name> | Reconnect a live MCP server. |
/memory list | List global and project memories. |
/memory show <name> | Show a memory entry. |
/memory forget <name> | Delete one memory entry. |
/memory clear <scope> confirm | Clear a memory scope. |
/permissions list | Show the workspace shell allowlist. |
/permissions add <prefix> | Add an approved shell prefix. |
/permissions rm <prefix|index> | Remove an approved shell prefix. |
/permissions clear confirm | Clear the workspace allowlist. |
/search-engine mojeek | Use Mojeek for web search. |
/search-engine searxng | Use local SearXNG at the default endpoint. |
/search-engine searxng http://192.168.1.5:8888 | Use a custom SearXNG endpoint. |
/search-engine metaso | Use Metaso for web search. |
/qq connect | Connect QQ to the active session. |
/pro | Use DeepSeek V4 Pro for the next turn. |
/preset max | Use Pro for the whole session. |
/help | Show in-session help. |
MCP Commands and Formats
| Item | Format or Command |
|---|---|
| MCP flag | npx reasonix code --mcp "fs=npx -y @mcp/server-filesystem /tmp" |
| MCP inspect | npx reasonix mcp inspect "git=uvx mcp-server-git" |
| MCP list | npx reasonix mcp list |
| Stdio string format | name=command arg1 arg2 |
| SSE URL format | remote=https://example.com/mcp/sse |
| Anonymous SSE URL | https://other.example.com/mcp |
| Streamable HTTP format | edge=streamable+https://edge.example.com/mcp |
Configuration Files and Paths
| Path or File | Purpose |
|---|---|
~/.reasonix/config.json | Global Reasonix config on macOS and Linux. |
%USERPROFILE%\.reasonix\config.json | Global Reasonix config on Windows. |
<project>/.reasonix/ | Project-level overrides. |
<project>/.reasonix/settings.json | Project hooks config. |
~/.reasonix/settings.json | Global hooks config. |
<project>/.reasonix/skills/ | Project skills. |
~/.reasonix/skills/ | Global skills. |
<project>/.claude/skills/<name>/SKILL.md | Claude-format project skills. |
~/.claude/skills/ | Claude-format global skills. |
~/.reasonix/memory/global/ | Global memory entries. |
~/.reasonix/memory/<project-hash>/ | Project memory entries. |
REASONIX.md | Repo-level project instruction file. |
Top-Level Config Keys
| Key | Supported Values or Purpose |
|---|---|
apiKey | DeepSeek API key. |
baseUrl | DeepSeek API base URL. |
lang | en or zh. |
preset | auto, flash, or pro. |
editMode | review, auto, or yolo. |
reasoningEffort | high or max. |
theme | light, dark, or auto. |
search | Enables or disables web search tools. |
webSearchEngine | mojeek, searxng, or metaso. |
webSearchEndpoint | Custom endpoint for search backends. |
mcp | Legacy MCP string entries. |
mcpServers | Canonical MCP server objects. |
mcpDisabled | MCP servers skipped at startup. |
projects | Per-workspace project overrides. |
semantic | Embedding provider config. |
session | Session config value. |
Edit Modes
| Mode | Behavior |
|---|---|
review | Queues edits and gates shell commands. |
auto | Applies edits and still gates shell commands. |
yolo | Skips edit and shell gates. Use only in a sandbox. |
MCP Server Object Keys
| Key | Use |
|---|---|
command | Stdio command. |
args | Stdio command arguments. |
env | Environment variables for stdio servers. |
transport | sse or streamable-http. |
url | HTTP server URL. |
headers | Headers for HTTP transports. |
disabled | Declarative server toggle. |
Skill Frontmatter
| Key | Supported Values or Purpose |
|---|---|
name | Skill name. |
description | One-line skill description. |
runAs | inline or subagent. |
allowed-tools | Tool allowlist for subagent mode. |
model | Subagent model override that must start with deepseek-. |
max-iters | Subagent tool-call budget from 1 to 32. |
Memory Entry Fields
| Field | Purpose |
|---|---|
name | Memory entry name. |
description | Memory summary. |
type | user, feedback, project, or reference. |
scope | Global or project memory scope. |
created | Creation date. |
| Body | The remembered fact in Markdown. |
Hook Events
| Event | Behavior |
|---|---|
PreToolUse | Runs before a tool call. Exit 2 blocks the tool. |
PostToolUse | Runs after a tool call. Non-zero exit warns only. |
UserPromptSubmit | Runs before user input enters the loop. Exit 2 blocks the prompt. |
Stop | Runs on /quit or session exit. Non-zero exit warns only. |
Semantic Index Config
| Provider | Key Fields |
|---|---|
ollama | baseUrl, model. |
openaiCompat | baseUrl, apiKey, model. |
Pros
- MIT open-source license.
- DeepSeek-native cache stability.
- Terminal-first coding workflow.
- MCP, skills, and hooks.
- Persistent per-workspace sessions.
- Review mode before edits.
- Desktop option.
Cons
- Paid DeepSeek API required.
- DeepSeek-only backend.
- No IDE replacement.
- Node setup required.
Alternatives and Related Resources
- 7 Best CLI AI Coding Agents in: Compare Reasonix with other popular AI coding agents.
- Free AI Coding Agents: Browse more free and open-source AI coding agents.
- DeepSeek TUI: Try another DeepSeek-focused AI coding agent.
- Claude Code Resource List: Explore Claude Code tools, skills, SDKs, and related projects.
- MCP Servers: Find MCP servers for agent workflows.
- Reasonix GitHub Repository: Open the code, issues, releases, and project files.
- Reasonix Configuration Guide: Review config keys, MCP setup, skills, memory, hooks, permissions, search, and indexing.
FAQs
Q: Is Reasonix free?
A: Reasonix is free to install and MIT licensed, but it requires a paid DeepSeek API key to run. API usage is billed by DeepSeek at standard token rates. The cache-first loop keeps costs low on long sessions, but every session incurs API charges.
Q: What operating systems does Reasonix support?
A: Reasonix supports macOS, Linux, and Windows. On Windows it works in PowerShell, Git Bash, and Windows Terminal.
Q: What is the difference between reasonix code and reasonix chat?
A: code mode gives the agent access to filesystem tools, a shell tool, and SEARCH/REPLACE edit review before changes apply. chat mode runs a lighter session with MCP servers and web search available but no disk or shell access. Use code for real coding tasks and chat when you want a model thinking partner with no file risk.
Q: Can Reasonix connect to MCP servers?
A: Yes. MCP servers attach through stdio, SSE, or Streamable HTTP.
