███╗   ██╗███████╗██╗  ██╗  ━   ██████╗ ██████╗ ██████╗ ███████╗
████╗  ██║██╔════╝╚██╗██╔╝  ━  ██╔════╝██╔═══██╗██╔══██╗██╔════╝
██╔██╗ ██║█████╗   ╚███╔╝   ━  ██║     ██║   ██║██║  ██║█████╗
██║╚██╗██║██╔══╝   ██╔██╗   ━  ██║     ██║   ██║██║  ██║██╔══╝
██║ ╚████║███████╗██╔╝ ██╗  ━  ╚██████╗╚██████╔╝██████╔╝███████╗
╚═╝  ╚═══╝╚══════╝╚═╝  ╚═╝  ━   ╚═════╝ ╚═════╝ ╚═════╝ ╚══════╝

Demo

https://github.com/user-attachments/assets/634e70eb-645c-42f7-a604-824f17e49840

Quickstart

npx nex-code

Or install globally:

npm install -g nex-code
cd ~/your-project
nex-code

That's it. You'll see the banner, your project context, and the > prompt. Start typing.

Automatic Updates

Nex Code automatically checks for new versions when you start it. If a newer version is available, you'll see a notification with instructions on how to update:

💡 New version available! Run npm update -g nex-code to upgrade from x.x.x to x.x.x

To update to the latest version:

npm update -g nex-code

Why nex-code?

| | nex-code | Claude Code | Gemini CLI | Aider | |---|---|---|---|---| | Free with Ollama | ✅ Native, first-class | ⚠️ Workaround | ❌ | ✅ | | Ollama Cloud support | ✅ 47+ models, native | ⚠️ API-compat only | ❌ | ✅ | | Multi-provider runtime swap | ✅ 5 providers, no restart | ❌ Claude-only | ❌ Gemini-only | ✅ | | Tool tiers (adapts to model) | ✅ essential/standard/full | ❌ | ❌ | ❌ | | 5-layer open-model auto-fix | ✅ | ❌ | ❌ | ⚠️ | | Undo / Redo | ✅ | ❌ | ❌ | ❌ | | Cost tracking + budgets | ✅ | ❌ | ❌ | ❌ | | Pre-push secret detection | ✅ | ❌ | ❌ | ❌ | | Browser agent (headless) | ✅ Playwright-based | ❌ | ⚠️ Experimental | ❌ | | Grounded web search | ✅ Perplexity/DDG | ❌ | ✅ Google grounded | ❌ | | GitHub Actions tools | ✅ native | ❌ | ❌ | ❌ | | Open-source | ✅ MIT | ❌ | ✅ Apache 2.0 | ✅ | | Runtime dependencies | 2 (axios, dotenv) | Many | Many | Heavy (Python) | | Startup time | ~100ms | ~400ms | ~300ms | Slow | | Test coverage | 1825 tests, 84% | — | — | — |

Ollama Cloud — The Free-by-Default Model Tier

nex-code was built with Ollama Cloud as its primary provider. No subscription, no billing surprises. Use powerful open models like Qwen3 Coder, Kimi K2.5, Devstral, and DeepSeek R1 for free.

| Model | Context | Best For | |---|---|---| | qwen3-coder:480b | 131K | Code generation, tool calling | | kimi-k2.5 | 256K | Large repos, reasoning | | devstral-2:123b | 131K | Reliable tool calling | | devstral-small-2:24b | 131K | Fast, efficient | | qwen3.5:35b-a3b | 256K | MoE, very fast |

Switch anytime: /model ollama:qwen3-coder:480b or add your OLLAMA_API_KEY to .env.

Setup

Prerequisites

• Node.js 18+
• At least one API key or a local Ollama server

Install from npm

npm install -g nex-code

Or run directly without installing:

npx nex-code

Install from source (for contributors)

git clone https://github.com/hybridpicker/nex-code.git
cd nex-code
npm install
npm run build         # Build the high-performance bundle
cp .env.example .env
npm link
npm run install-hooks

Configure a Provider

Create a .env file in your project directory (or set environment variables):

# Pick any — only one is required
OLLAMA_API_KEY=your-key       # Ollama Cloud (Qwen3 Coder, Qwen3.5, DeepSeek R1, Devstral, Kimi K2.5, Llama 4, MiniMax M2.5, GLM 4.7)
OPENAI_API_KEY=your-key       # OpenAI (GPT-4o, GPT-4.1, o1, o3, o4-mini)
ANTHROPIC_API_KEY=your-key    # Anthropic (Claude Sonnet 4.6, Opus 4.6, Haiku 4.5)
GEMINI_API_KEY=your-key       # Google Gemini (3.1 Pro Preview, 2.5 Pro/Flash, 2.0 Flash)
PERPLEXITY_API_KEY=your-key   # Perplexity (optional — enables grounded web search)
# No key needed for local Ollama — just have it running

# Optional tuning
DEFAULT_PROVIDER=ollama        # Active provider on startup
DEFAULT_MODEL=qwen3-coder:480b # Active model on startup
FALLBACK_CHAIN=anthropic,openai # Providers tried on failure (comma-separated)
NEX_STALE_WARN_MS=60000        # Warn if no tokens received for N ms (default: 60000)
NEX_STALE_ABORT_MS=120000      # Abort and retry stream after N ms of silence (default: 120000)

Verify

cd ~/any-project
nex-code

You should see the banner, your project context, and the > prompt.

Usage

> explain the main function in index.js
> add input validation to the createUser handler
> run the tests and fix any failures
> refactor this to use async/await instead of callbacks

Try These Scenarios

Understand an unfamiliar codebase:

> give me an overview of this project — architecture, key files, tech stack
> how does authentication work here? trace the flow from login to session
> find all API endpoints and list them with their HTTP methods

Fix bugs with context:

> the /users endpoint returns 500 — find the bug and fix it
> tests are failing in auth.test.js — figure out why and fix it
> there's a memory leak somewhere — profile the app and find it

Add features end-to-end:

> add rate limiting to all API routes (100 req/min per IP)
> add a /health endpoint that checks DB connectivity
> implement pagination for the GET /products endpoint

Refactor and improve:

> refactor the database queries to use a connection pool
> this function is 200 lines — break it into smaller functions
> migrate these callbacks to async/await

DevOps and CI:

> write a Dockerfile for this project
> set up GitHub Actions CI that runs tests on push
> add a pre-commit hook that runs linting

Multi-step autonomous work (YOLO mode):

nex-code -yolo

> read the entire src/ directory, run the tests, fix all failures, then commit
> add input validation to every POST endpoint, add tests, run them
> upgrade all dependencies to latest, fix any breaking changes, run tests

The agent decides autonomously whether to use tools or just respond with text. Simple questions get direct answers. Coding tasks trigger the agentic tool loop.

Vision / Screenshot → Code — drop an image path anywhere in your message and nex-code will send it to a vision-capable model automatically:

> /path/to/screenshot.png implement this UI in React
> describe the layout in mockup.png and generate the CSS

Supported formats: PNG, JPG, GIF, WebP, BMP. Works with Anthropic, OpenAI, Gemini, and Ollama vision models (llava, qwen2-vl, etc.).

YOLO Mode

Skip all confirmation prompts — file changes, dangerous commands, and tool permissions are auto-approved. The banner shows a ⚡ YOLO indicator. Toggle at runtime with /autoconfirm.

Headless / Programmatic Mode

Run nex-code non-interactively from scripts, CI pipelines, or other processes:

# Inline prompt
nex-code --task "refactor src/index.js to use async/await" --yolo

# Prompt from file (avoids shell-escaping issues with special characters)
nex-code --prompt-file /tmp/task.txt --yolo

# Delete the file after reading
nex-code --prompt-file /tmp/task.txt --delete-prompt-file --yolo

# JSON output for programmatic parsing
nex-code --prompt-file /tmp/task.txt --yolo --json
# → {"success":true,"response":"..."}

| Flag | Description | |------|-------------| | --task <prompt> | Run a single prompt and exit | | --prompt-file <path> | Read prompt from a UTF-8 file and run headless | | --delete-prompt-file | Delete the prompt file after reading (use with --prompt-file) | | --auto | Skip confirmations (non-interactive, no REPL banner) | | --yolo | Skip all confirmations including dangerous commands | | --json | Output {"success":true,"response":"..."} to stdout | | --max-turns <n> | Override the agentic loop iteration limit | | --model <spec> | Use a specific model (e.g. anthropic:claude-sonnet-4-6) |

Providers & Models

Switch providers and models at runtime:

/model                         # interactive model picker (arrow keys + Enter)
/model openai:gpt-4o           # switch directly
/model anthropic:claude-sonnet
/model gemini:gemini-2.5-pro
/model local:llama3
/providers                     # see all available providers & models

| Provider | Models | Env Variable | |----------|--------|-------------| | ollama | Qwen3 Coder, Qwen3.5 (397B, 122B-A10B, 35B-A3B, 27B, 9B, 4B, 2B, 0.8B), DeepSeek R1, Devstral, Kimi K2.5, MiniMax M2.5, GLM 4.7, Llama 4 | OLLAMA_API_KEY | | openai | GPT-4o, GPT-4.1, o1, o3, o4-mini | OPENAI_API_KEY | | anthropic | Claude Sonnet 4.6, Opus 4.6, Haiku 4.5, Sonnet 4.5, Sonnet 4 | ANTHROPIC_API_KEY | | gemini | Gemini 3.1 Pro Preview, 2.5 Pro/Flash, 1.5 Pro/Flash | GEMINI_API_KEY | | local | Any model on your local Ollama server | (none) |

Fallback chains let you auto-switch when a provider fails:

/fallback anthropic,openai,local

Commands

Type / to see inline suggestions as you type. Tab completion is supported for slash commands and file paths (type a path containing / and press Tab).

| Command | Description | |---------|-------------| | /help | Full help | | /model [spec] | Show/switch model (e.g. openai:gpt-4o) | | /providers | List all providers and models | | /fallback [chain] | Show/set fallback chain | | /tokens | Token usage and context budget | | /costs | Session token costs | | /budget | Show/set per-provider cost limits | | /clear | Clear conversation | | /context | Show project context | | /autoconfirm | Toggle auto-confirm for file changes | | /save [name] | Save current session | | /load <name> | Load a saved session | | /sessions | List saved sessions | | /resume | Resume last session | | /remember <text> | Save a memory (persists across sessions) | | /forget <key> | Delete a memory | | /memory | Show all memories | | /permissions | Show tool permissions | | /allow <tool> | Auto-allow a tool | | /deny <tool> | Block a tool | | /plan [task] | Plan mode (analyze before executing) | | /plans | List saved plans | | /auto [level] | Set autonomy: interactive/semi-auto/autonomous | | /commit [msg] | Smart commit (analyze diff, suggest message) | | /diff | Show current diff | | /branch [name] | Create feature branch | | /mcp | MCP servers and tools | | /hooks | Show configured hooks | | /skills | List, enable, disable skills | | /undo | Undo last file change | | /redo | Redo last undone change | | /history | Show file change history | | /review [file] | Code review on current diff or a specific file | | /exit | Quit |

Tools

The agent has 17 built-in tools:

| Tool | Description | |------|-------------| | bash | Execute shell commands (90s timeout, 5MB buffer) | | read_file | Read files with optional line range (binary detection) | | write_file | Create or overwrite files (with diff preview + confirmation) | | edit_file | Targeted text replacement (with diff preview + confirmation) | | patch_file | Atomic multi-replacement in a single operation | | list_directory | Tree view with depth control and glob filtering | | search_files | Regex search across files (like grep) | | glob | Fast file search by name/extension pattern | | grep | Content search with regex and line numbers | | git_status | Git working tree status | | git_diff | Git diff with optional path filter | | git_log | Git commit history with configurable count | | web_fetch | Fetch content from a URL | | web_search | Grounded search via Perplexity (if PERPLEXITY_API_KEY set) or DuckDuckGo | | ask_user | Ask the user a question and wait for input | | task_list | Create and manage task lists for multi-step operations | | spawn_agents | Run parallel sub-agents with auto model routing | | browser_open | Open URL in headless browser, return text + links (JS-heavy pages) | | browser_screenshot | Screenshot a URL → saved file + vision-ready path | | browser_click | Click element by CSS selector or visible text | | browser_fill | Fill form field and optionally submit | | gh_run_list | List GitHub Actions workflow runs | | gh_run_view | View run details and step logs | | gh_workflow_trigger | Trigger a workflow dispatch event |

Interactive commands (vim, top, htop, ssh, tmux, fzf, etc.) are automatically detected and spawned with full TTY passthrough — no separate handling required.

Browser tools require Playwright (npm install playwright && npx playwright install chromium). nex-code works without it — browser tools return a helpful install message if missing.

Additional tools can be added via MCP servers or Skills.

Features

Compact Output

The agent loop uses a single spinner during tool execution, then prints compact 1-line summaries:

  ⠋ ▸ 3 tools: read_file, grep, edit_file
  ✓ read_file src/app.js (45 lines)
  ✓ grep TODO → 12 matches
  ✗ edit_file src/x.js → old_text not found

After multi-step tasks, a résumé and context-aware follow-up suggestions are shown:

  ── 3 steps · 8 tools · 2 files modified · 37s ──
  💡 /diff · /commit · /undo

Step counts match between inline ── step N ── markers and the résumé. Elapsed time is included. Read-heavy sessions (analysis, status checks) suggest /save · /clear instead.

When the model runs tools but produces no visible text, an automatic nudge forces it to summarize findings — preventing silent completions where the user sees nothing.

Response Quality

The system prompt enforces substantive responses: the model always presents findings as formatted text after using tools (users only see 1-line tool summaries). Responses use markdown with headers, bullet lists, and code blocks. The model states its approach before non-trivial tasks and summarizes results after completing work.

Performance

• Asynchronous I/O: The entire CLI is built on non-blocking I/O. File reads, writes, and git operations never block the main thread, keeping the UI responsive even during heavy tasks.
• Fast Startup: Pre-bundled with esbuild to minimize module loading overhead, achieving sub-100ms startup times.
• In-Memory Indexing: A background indexing engine (using ripgrep or a fast fallback) keeps project file paths in RAM for instant file discovery, path auto-fixing, and glob searches.

Streaming Output

Tokens appear live as the model generates them. Braille spinner during connection, then real-time line-by-line rendering via StreamRenderer with markdown formatting and syntax highlighting (JS, TS, Python, Go, Rust, CSS, HTML, and more).

Paste Detection

Automatic bracketed paste mode: pasting multi-line text into the prompt is detected and combined into a single input. A [Pasted content — N lines] indicator is shown with a preview of the first line. The user must press Enter to send — pasted content never auto-fires. The paste handler stores the combined text and waits for explicit submission.

Ctrl+C Cancellation

Pressing Ctrl+C during a running request immediately cancels the active HTTP stream and returns to the prompt:

• An AbortController signal flows from the readline SIGINT handler through the agent loop to the provider's HTTP request
• All providers (Ollama, OpenAI, Anthropic, Gemini, local) destroy the response stream on abort
• No EPIPE errors after cancellation (stdout writes are EPIPE-guarded)
• During processing: first Ctrl+C aborts the task and returns to prompt; second Ctrl+C force-exits
• At the idle prompt: first Ctrl+C shows (Press Ctrl+C again to exit), second Ctrl+C exits (hint resets after 2 s)
• readline intercepts Ctrl+C on TTY (rl.on('SIGINT')) to prevent readline close → process.exit(0) race

Diff Preview

Every file change is shown in a diff-style format before being applied:

• Header: ⏺ Update(file) or ⏺ Create(file) with relative path
• Summary: ⎿ Added N lines, removed M lines
• Numbered lines: right-justified line numbers with red - / green + markers
• Context: 3 lines of surrounding context per change, multiple hunks separated by ···
• OOM-safe: large diffs (>2000 lines) fall back to add/remove instead of LCS
• All changes require [y/n] confirmation (toggle with /autoconfirm or start with -yolo)

Auto-Context

On startup, the CLI reads your project and injects context into the system prompt:

• package.json — name, version, scripts, dependencies
• README.md — first 50 lines
• Git info — branch, status, recent commits
• .gitignore content
• Merge conflicts — detected and shown as a red warning; included in LLM context so the agent avoids editing conflicted files

Context Engine

Automatic token management with compression when the context window gets full. Tracks token usage across system prompt, conversation, tool results, and tool definitions.

Safety Layer

Three tiers of protection:

• Forbidden (blocked): rm -rf /, rm -rf ., mkfs, dd if=, fork bombs, curl|sh, cat .env, chmod 777, reverse shells — 30+ patterns
• Dangerous (requires confirmation): git push, npm publish, rm -rf, docker rm, sudo, ssh — 14 patterns
• SSH read-only safe list: Common read-only SSH commands (systemctl status, journalctl, tail, cat, git pull, etc.) skip the dangerous-command confirmation
• Path protection: Sensitive paths (.ssh/, .aws/, .env, credentials) are blocked from file operations
• Pre-push secret detection: Git hook scans diffs for API keys, private keys, hardcoded secrets, SSH+IP patterns, and .env leaks before allowing push
• Post-merge automation: Auto-bumps patch version on devel→main merge; runs npm install when package.json changes

Sessions

Save and restore conversations:

/save my-feature
/load my-feature
/resume              # resume last session

Auto-save after every turn.

Memory

Persistent project memory that survives across sessions:

/remember lang=TypeScript
/remember always use yarn instead of npm
/memory
/forget lang

Also loads NEX.md from project root for project-level instructions.

Plan Mode

Analyze before executing — the agent explores the codebase with read-only tools, produces a structured plan, then you approve before any changes are made:

/plan refactor the auth module   # enter plan mode
/plan status                     # show plan progress
/plan approve                    # approve and exit plan mode (all tools re-enabled)
/auto semi-auto                  # set autonomy level

Plan mode is hard-enforced: only read-only tools (read_file, list_directory, search_files, glob, grep, web_search, web_fetch, git_status, git_diff, git_log, git_show, ask_user) are available. Any attempt to call a write tool is blocked at the API level — the LLM cannot make changes even if it tries. The plan text is saved to .nex/plans/current-plan.md for review.

Undo / Redo

In-session undo/redo for all file changes (write, edit, patch):

/undo                # undo last file change
/redo                # redo last undone change
/history             # show file change history

Undo stack holds up to 50 changes. /clear resets the history.

Task Management

Create structured task lists for complex multi-step operations:

/tasks                # show current task list
/tasks clear          # clear all tasks

The agent uses task_list to create, update, and track progress on tasks with dependency support.

When the agent creates a task list, a live animated display replaces the static output:

✽ Adding cost limit functions… (1m 35s · ↓ 2.6k tokens)
  ⎿  ✔ Create cli/picker.js — Interactive Terminal Picker
     ◼ Add cost limits to cli/costs.js
     ◻ Add budget gate to cli/providers/registry.js
     ◻ Update cli/index.js
     ◻ Run tests

• Animated spinner header with elapsed time and cumulative token count
• Per-task status icons: ✔ done, ◼ in progress, ◻ pending, ✗ failed
• Automatically pauses during text streaming and resumes during tool execution
• Falls back to the static /tasks view when no live display is active

Sub-Agents

Spawn parallel sub-agents for independent tasks:

• Up to 5 agents run simultaneously with their own conversation contexts
• File locking prevents concurrent writes to the same file
• Multi-progress display shows real-time status of each agent
• Good for: reading multiple files, analyzing separate modules, independent research

Multi-Model Routing — Sub-agents auto-select the best model per task based on complexity:

• Read/search/list tasks → fast models (essential tier)
• Edit/fix/analyze tasks → capable models (standard tier)
• Refactor/implement/generate tasks → most powerful models (full tier)

The LLM can also explicitly override with model: "provider:model" in the agent definition. When multiple providers are configured, the system prompt includes a routing table showing all available models and their tiers.

Git Intelligence

/commit              # analyze diff, suggest commit message
/commit feat: add login
/diff                # show current diff summary
/branch my-feature   # create and switch to branch

Permissions

Control which tools the agent can use:

/permissions         # show current settings
/allow read_file     # auto-allow without asking
/deny bash           # block completely

Persisted in .nex/config.json.

Cost Tracking

Track token usage and costs per provider:

/costs
/costs reset

Cost Limits

Set per-provider spending limits. When a provider exceeds its budget, calls automatically fall back to the next provider in the fallback chain:

/budget                    # show all limits + current spend
/budget anthropic 5        # set $5 limit for Anthropic
/budget openai 10          # set $10 limit for OpenAI
/budget anthropic off      # remove limit

Limits are persisted in .nex/config.json. You can also set them directly:

// .nex/config.json
{
  "costLimits": {
    "anthropic": 5,
    "openai": 10
  }
}

Open-Source Model Robustness

Four features that make Nex Code significantly more reliable with open-source models:

Tool Call Retry with Schema Hints — When a model sends malformed tool arguments, instead of a bare error, the agent sends back the expected JSON schema so the model can self-correct on the next loop iteration.

Smart Argument Parsing — 5 fallback strategies for parsing tool arguments: direct JSON, trailing comma/quote fixes, JSON extraction from surrounding text, unquoted key repair, and markdown code fence stripping (common with DeepSeek R1, Llama).

Tool Argument Validation — Validates arguments against tool schemas before execution. Auto-corrects similar parameter names (Levenshtein distance), fixes type mismatches (string↔number↔boolean), and provides "did you mean?" suggestions.

Auto-Fix Engine — Three layers of automatic error recovery that silently fix common tool failures:

• Path auto-fix: Wrong extension? Finds the right one (.js → .ts). File moved? Globs for it by basename. Double slashes, missing extensions — all auto-resolved.
• Edit auto-fix: Close match (≤5% Levenshtein distance) in edit_file/patch_file is auto-applied instead of erroring. Stacks with fuzzy whitespace matching.
• Bash error hints: Enriches error output with actionable hints — "command not found" → install suggestion, MODULE_NOT_FOUND → npm install <pkg>, port in use, syntax errors, TypeScript errors, test failures, and more.

Stale Stream Recovery — Progressive retry strategy when streams stall (common with large Ollama models after many agent steps):

• 1st retry: 3s backoff delay, resend same context (handles transient stalls)
• 2nd retry: force-compress conversation (~80k tokens freed), 5s delay, retry with smaller context
• Last resort: if retries exhausted, one final force-compress + reset for fresh attempts
• Broader context-too-long detection catches Ollama-specific error formats (num_ctx, prompt, size, exceeds)

Tool Tiers — Dynamically reduces the tool set based on model capability:

• essential (5 tools): bash, read_file, write_file, edit_file, list_directory
• standard (13 tools): + search_files, glob, grep, ask_user, git_status, git_diff, git_log, task_list
• full (17 tools): all tools

Models are auto-classified, or override per-model in .nex/config.json:

{
  "toolTiers": {
    "deepseek-r1": "essential",
    "local:*": "essential",
    "qwen3-coder": "full"
  },
  "maxIterations": 100
}

maxIterations sets the agentic loop limit project-wide (default: 50). The --max-turns <n> CLI flag overrides it per run.

Tiers are also used by sub-agent routing — when a sub-agent auto-selects a model, its tool set is filtered to match that model's tier.

Skills

Extend Nex Code with project-specific knowledge, commands, and tools via .nex/skills/.

Prompt Skills (.md)

Drop a Markdown file and its content is injected into the system prompt:

<!-- .nex/skills/code-style.md -->
# Code Style
- Always use semicolons
- Prefer const over let
- Use TypeScript strict mode

Script Skills (.js)

CommonJS modules that can provide instructions, slash commands, and tools:

// .nex/skills/deploy.js
module.exports = {
  name: 'deploy',
  description: 'Deployment helper',
  instructions: 'When deploying, always run tests first...',
  commands: [
    { cmd: '/deploy', desc: 'Run deployment', handler: (args) => { /* ... */ } }
  ],
  tools: [
    {
      type: 'function',
      function: { name: 'deploy_status', description: 'Check status', parameters: { type: 'object', properties: {} } },
      execute: async (args) => 'deployed'
    }
  ]
};

Management

/skills                    # list loaded skills
/skills enable code-style  # enable a skill
/skills disable code-style # disable a skill

Skills are loaded on startup. All enabled by default. Disabled skills tracked in .nex/config.json.

MCP

Connect external tool servers via the Model Context Protocol:

// .nex/config.json
{
  "mcpServers": {
    "my-server": {
      "command": "node",
      "args": ["path/to/server.js"]
    }
  }
}

/mcp              # show servers and tools
/mcp connect      # connect all configured servers
/mcp disconnect   # disconnect all

MCP tools appear with the mcp_ prefix and are available to the agent alongside built-in tools.

Hooks

Run custom scripts on CLI events:

// .nex/config.json
{
  "hooks": {
    "pre-tool": ["echo 'before tool'"],
    "post-tool": ["echo 'after tool'"],
    "pre-commit": ["npm test"]
  }
}

Events: pre-tool, post-tool, pre-commit, post-response, session-start, session-end.

Or place executable scripts in .nex/hooks/:

.nex/hooks/pre-tool
.nex/hooks/post-tool

Architecture

bin/nex-code.js          # Entrypoint (shebang, .env, startREPL)
cli/
├── index.js             # REPL + ~38 slash commands + history persistence + AbortController
├── agent.js             # Agentic loop + conversation state + compact output + résumé + abort handling
├── providers/           # Multi-provider abstraction
│   ├── base.js          # Abstract provider interface
│   ├── ollama.js        # Ollama Cloud provider
│   ├── openai.js        # OpenAI provider
│   ├── anthropic.js     # Anthropic provider
│   ├── gemini.js        # Google Gemini provider
│   ├── local.js         # Local Ollama server
│   └── registry.js      # Provider registry + model resolution + provider routing
├── tools.js             # 17 tool definitions + implementations + auto-fix engine
├── sub-agent.js         # Parallel sub-agent runner with file locking + model routing
├── tasks.js             # Task list management (create, update, render, onChange callbacks)
├── skills.js            # Skills system (prompt + script skills)
├── mcp.js               # MCP client (JSON-RPC over stdio)
├── hooks.js             # Hook system (pre/post events)
├── context.js           # Auto-context (package.json, git, README)
├── context-engine.js    # Token management + context compression
├── session.js           # Session persistence (.nex/sessions/)
├── memory.js            # Project memory (.nex/memory/ + NEX.md)
├── permissions.js       # Tool permission system
├── planner.js           # Plan mode + autonomy levels
├── git.js               # Git intelligence (commit, diff, branch)
├── render.js            # Markdown + syntax highlighting + StreamRenderer + EPIPE guard
├── format.js            # Tool call formatting, result formatting, compact summaries
├── spinner.js           # Spinner, MultiProgress, TaskProgress display components
├── diff.js              # LCS diff (Myers + Hirschberg) + colored output + side-by-side view
├── fuzzy-match.js       # Fuzzy text matching for edit auto-fix (Levenshtein, whitespace normalization)
├── file-history.js      # In-session undo/redo for file changes
├── picker.js            # Interactive terminal picker (model selection)
├── costs.js             # Token cost tracking + per-provider budget limits
├── safety.js            # Forbidden/dangerous pattern detection
├── tool-validator.js    # Tool argument validation + auto-correction
├── tool-tiers.js        # Dynamic tool set selection per model + model tier lookup
├── ui.js                # ANSI colors, banner + re-exports from format.js/spinner.js
├── index-engine.js      # In-memory file index (ripgrep/fallback)
├── auto-fix.js          # Path resolution, edit matching, bash error hints
├── tool-retry.js        # Malformed argument retry with schema hints
└── ollama.js            # Backward-compatible wrapper

Agentic Loop

User Input --> [AbortController created]
    |
[System Prompt + Context + Memory + Skills + Conversation]
    |
[Filter tools by model tier (essential/standard/full)]
    |
Provider API (streaming + abort signal) --> Text tokens --> rendered to terminal
    |                   \--> Tool calls --> parse args (5 strategies)
    |                                       |
    |                              [Validate against schema + auto-correct]
    |                                       |
    |                              Execute (skill / MCP / built-in)
    |                                       |
    |                              [Auto-fix: path resolution, edit matching, bash hints]
    |
[Tool results added to history]
    |
Loop until: no more tool calls OR 50 iterations OR Ctrl+C abort

.nex/ Directory

Project-local configuration and state (gitignored):

.nex/
├── config.json        # Permissions, MCP servers, hooks, skills, cost limits
├── sessions/          # Saved conversations
├── memory/            # Persistent project knowledge
├── plans/             # Saved plans
├── hooks/             # Custom hook scripts
├── skills/            # Skill files (.md and .js)
└── push-allowlist     # False-positive allowlist for pre-push secret detection

Performance

Nex Code v0.3.7+ includes comprehensive performance optimizations:

| Optimization | Improvement | Impact | |--------------|-------------|--------| | System Prompt Caching | 4.3× faster | 77µs → 18µs | | Token Estimation Caching | 3.5× faster | Cached after first call | | Context File Caching | 10-20× faster | 50-200ms → 5-10ms | | Debounced Auto-Save | 0ms in hot path | Saves after 5s inactivity | | Tool Filter Caching | 1.7× faster | Cached per model | | Schema Cache | 3.4× faster | 2.51µs → 0.73µs |

Average speedup: 2.7× (micro-benchmarks)
Real-world improvement: ~10× faster per turn

Run benchmarks yourself:

node benchmark.js

Testing

npm test              # Run all tests with coverage
npm run test:watch    # Watch mode

47 test suites, 1825 tests, 84% statement / 77% branch coverage.

CI runs on GitHub Actions (Node 18/20/22).

Dependencies

2 runtime dependencies:

{
  "axios": "^1.7.0",
  "dotenv": "^16.4.0"
}

Everything else is Node.js built-in.

Installation

npm install -g nex-code    # global install
npx nex-code               # or run without installing

Roadmap

See ROADMAP.md for planned features — VS Code extension, browser agent, PTY support, and more. Community contributions are welcome on all roadmap items.

License

MIT