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DevLens Demo

Click the image to watch the demo

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Table of Contents

• About
• Who is this for
• Quick Start
• The Problem DevLens Solves
• Benchmarks
• Ways to Use DevLens
  • Web UI
  • CLI
  • Agent Skill
  • MCP Server
• Configuration
• What DevLens Understands
• Repository Layout
• DevLens Cloud

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About

DevLens is a codebase visualizer for JavaScript, TypeScript, React, Next.js, and Node.js projects. It builds a typed dependency graph of every component, hook, function, route, and store — with AI-powered summaries on each node — so you can explore, understand, and analyze your architecture in seconds instead of hours.

What makes it different? Instead of reading files one at a time, you (or your AI agent) query the pre-built graph. A node summary costs ~50 tokens vs ~2,000 tokens per file.

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Who Is This For

Developers & Teams

• Onboard new devs in hours, not weeks — explore the graph instead of spelunking files.
• Review PRs with full context — see exactly what depends on each change.
• Run impact analysis before refactoring — "what breaks if I change this?"
• Catch circular deps, god-files, and coupling hotspots automatically.
• Keep living documentation — summaries stay fresh as code changes.

Engineering Leaders

• Get a bird's-eye view of your entire codebase in seconds.
• Spot architectural debt before it becomes a crisis.
• Understand what your team has been building — even across repos.

Students & Learners

• See how real codebases are designed — layers, patterns, data flow.
• Understand why things are connected, not just what each file does.
• Learn architecture patterns from production-grade projects.

AI-Augmented Developers

Your agent burns tokens re-reading files it's seen before. DevLens gives it a graph to query instead.

Coming soon — DevLens Cloud: Shareable graphs your whole team can access, cross-repo navigation, and giving graphical context to your AI agents for smarter code review and analysis — all without running anything locally.

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Quick Start

1. Install

npm install -g @devlensio/cli

No Node.js? Use the standalone binary installer (no dependencies):

Linux / macOS:

curl -fsSL https://raw.githubusercontent.com/devlensio/devlensOSS/main/scripts/install.sh | sh

Windows (PowerShell):

irm https://raw.githubusercontent.com/devlensio/devlensOSS/main/scripts/install.ps1 | iex

2. Init

cd your-project
devlens init

This sets up your LLM provider for AI summaries. Don't need AI? Skip this — structural analysis works offline.

3. Analyze

devlens analyze . --summarize

This builds a typed dependency graph of every component, hook, function, route, and store — with AI-powered summaries on each node.

4. Explore

devlens overview                  # big picture: framework, stats, central nodes
devlens find-nodes -t ROUTE       # find every route in the app
devlens security                  # see security flags across the codebase

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The Problem DevLens Solves

AI coding tools let you ship faster than ever — but that speed creates AI debt: code merged without understanding, agents re-discovering connections every session, new hires drowning in unfamiliar structure.

DevLens fixes this by pre-building a typed dependency graph of your entire codebase. Every node gets:

• Functional summary — what business purpose does this serve?
• Technical summary — how does it work?
• Security assessment — severity + explanation

Armed with this graph, you (or your AI agent) can understand the full architecture in ~50 tokens per node instead of ~2,000 per file.

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Benchmarks

Tested across real-world tasks — architecture understanding, feature implementation, and bug finding — comparing the same model (DeepSeek V4 Flash, GLM 5.2, Kimi K2.6, Qwen 3.6) with and without DevLens.

Architecture Understanding (4 models, full DevLens MCP)

Metric	Without DevLens	With DevLens	Improvement
Avg cost per query	$0.163	$0.075	54% cheaper
Avg input tokens	88,980	35,035	61% less
Avg output tokens	9,549	3,233	66% less
Avg tool steps	14.3	7.8	45% faster
Structured architecture output	50%	100%	2× more reliable
Architectural debt discovered	0%	50%	Now discoverable
Avg cache hit rate	75.2%	83.7%	+8.5pp

Notable: Even the strongest model (DeepSeek V4 Flash) was 81% cheaper ($0.0035 vs $0.0185) and used 83% fewer input tokens with DevLens.

Feature Implementation & Bug Finding (DeepSeek V4 Flash)

5 prompts across implementation and debugging tasks — DevLens graph context only (no per-node summaries).

Task	Input tokens saved	Cache improvement
Continue Watching feature	24% less input (56.8k vs 74.9k)	+5.2pp cache
Rate Limiting feature	22% less input (32.1k vs 41.1k)	+8.3pp cache
Error Handling audit	(comparable)	Comparable
Profile Bug trace	32% less input (36.9k vs 54.3k)	Similar

Quality Impact (Architecture Task)

When asked to explain a codebase's architecture:

Capability	Without DevLens	With DevLens
Produced structured output	50%	100%
Referenced specific graph metrics	0%	100%
Identified architectural debt	0%	50%
Named specific important files	75%	100%

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Ways to Use DevLens

Pick the interface that fits your workflow.

Web UI — Visual Exploration

For when you want to see your codebase laid out as an interactive graph.

Open the Web UI, paste your repo path, and explore a force-directed canvas — click any node to see its summaries, callers, callees, and security flags. Search, filter, diff commits across versions.

git clone https://github.com/devlensio/devlensOSS.git
cd devlensOSS && bun install && bun run dev

CLI (@devlensio/cli) — Terminal Power

For scripts, CI, and when you want answers fast without leaving the terminal.

npm install -g @devlensio/cli

Command	Description	Example
devlens analyze .	Analyze a repository into a DevLens graph	devlens analyze ./my-app --summarize
devlens overview	Big picture — framework, stats, central nodes	devlens overview → "Next.js 15, 342 nodes, 12 routes, top node: Layout (9.2)"
devlens blast-radius <nodeId>	What breaks if I change this?	devlens blast-radius "src/auth.ts::login" → "14 dependents affected"
devlens cycles	Find circular dependencies	devlens cycles → Lists every circular import group
devlens find-nodes -t <type>	Filter nodes by type (ROUTE, COMPONENT, etc.)	devlens find-nodes -t ROUTE → Lists all 12 routes
devlens find-nodes --severity high	Find high-severity security issues	devlens find-nodes --severity high → "2 findings in auth module"
devlens diff <from> <to>	Compare two analyzed commits	devlens diff abc123 def456 → "Added: AnalyticsTracker, Changed: CheckoutForm"
devlens security	List every security issue	devlens security --min-severity high --json
devlens config	View configuration with all saved providers	devlens config
devlens config set	Interactive provider configuration with live model fetching	devlens config set
devlens config --active <key>	Switch active provider without re-entering credentials	devlens config --active openai:deepseek
devlens config --remove <key>	Remove a saved provider entry	devlens config --remove anthropic:anthropic

Each command supports --json for piping into scripts and CI pipelines, -v/--verbose for diagnostics, and --quiet for minimal output.

Full reference: src/cli/README.md — every command with examples and options.

Agent Skill (@devlensio/skill) — AI-Powered Understanding

The most powerful way to use DevLens. Your AI agent normally reads files one at a time — the DevLens Skill teaches it to query the pre-built graph instead.

npx @devlensio/skill install

Then reload your tool and use /devlens in Claude Code, Cursor, or Kilo:

Command	Description	Example
/devlens architecture	Full system overview — stack, modules, routes, patterns	/devlens architecture → Returns structured report: framework, 12 routes, 3 modules, security posture
/devlens security-analysis	Prioritized security findings with exploit notes	/devlens security-analysis high → "SQL injection in loginUser (reach: 14 nodes)"
/devlens impact <symbol>	Blast radius — what breaks if you change this?	/devlens impact loginUser → "14 dependents across 3 modules"
/devlens tech-debt	Circular deps, coupling hotspots, god-files	/devlens tech-debt → "3 cycles, Navbar has 28 dependents"
/devlens guard [target]	Warn before editing high-risk code	/devlens guard → "⚠️ authMiddleware affects 22 dependents"
/devlens onboard	Generate ONBOARDING.md for new devs	/devlens onboard → Writes full onboarding doc to repo root
/devlens explain [path]	Understand a module with callers/callees	/devlens explain src/api/ → Walks through all API handlers
/devlens find <name>	Locate any component, hook, or function	/devlens find Button → "3 matches across components and tests"
/devlens changes [range]	Explain what changed and its impact	/devlens changes yesterday → "3 files, 2 features, 1 bug fix"
/devlens diagram [type]	Mermaid diagrams of architecture or flows	/devlens diagram architecture → Generates layered module diagram

Full reference: packages/skill-installer/README.md — all subcommands with examples, install options, and supported tools.

MCP Server — For Any MCP-Compatible AI Agent

Wire DevLens into any MCP client (Claude Desktop, IDE plugins, etc.). Bundled inside the CLI — exposes 14 tools over the Model Context Protocol.

devlens mcp                       # stdio mode
claude mcp add devlens -- devlens mcp   # register in Claude Code
devlens mcp http -p 7000          # HTTP mode

Each MCP tool is a query into the pre-built graph — your agent can:

• list_analyzed_repos — see what repos are already analyzed
• get_repo_overview — framework, stats, route count at a glance
• find_nodes — search by name, type, file, severity, or score
• get_blast_radius — check impact before refactoring
• get_security_issues — rank all security findings
• list_cycles — find circular dependencies
• analyze_changes — diff two analyzed commits

Full reference: src/mcp/README.md — tool reference, examples, registration, and configuration.

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Configuration

Config lives in ~/.devlens/config.json — set via devlens init or devlens config.

Provider	Recommended model	Notes
Ollama (local)	qwen2.5-coder:7b	Free, local, 8GB+ RAM
OpenAI	gpt-4o-mini	Fast, cost-effective
Anthropic	claude-haiku-4-5	Best cost/quality for summaries
DeepSeek	deepseek-v4-flash	Strong code model
OpenRouter	deepseek-v4-flash or mimo-v2.5	Best cost/quality balance
Gemini	gemini-2.0-flash	Fast, large context

# Interactive setup — picks from a catalog and fetches live model lists
devlens config set

# Non-interactive scripting
devlens config --provider openai --provider-name deepseek --model deepseek-v4-flash --api-key <key>

# Switch between saved providers without re-entering credentials
devlens config --active openai:deepseek

Models are discovered dynamically from each provider's /models endpoint — no hardcoded model lists. Custom OpenAI- or Anthropic-compatible endpoints can be added through the interactive flow.

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What DevLens Understands

Node types: COMPONENT, HOOK, FUNCTION, STATE_STORE, UTILITY, FILE, ROUTE, TEST, STORY, THIRD_PARTY

Route types: Next.js (app & pages), Express / Fastify / Koa, React Router / TanStack Router / wouter

Edge types: CALLS, IMPORTS, READS_FROM, WRITES_TO, PROP_PASS, EMITS, LISTENS, WRAPPED_BY, GUARDS, HANDLES, TESTS, USES, NEXTJS_API_CALL, NAVIGATES_TO

Per node: Importance score + functional summary + technical summary + security assessment

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Repository Layout

devlensOSS/
├── src/
│   ├── cli/                  # `devlens` CLI (commander program + commands)
│   ├── core/                 # Shared query core (CLI + MCP — never drift)
│   ├── mcp/                  # MCP server (stdio + HTTP), 14 tools
│   └── server/               # Backend API for the Web UI
├── frontend/                 # Next.js 15 graph visualizer (Cytoscape)
├── plugins/devlens/          # Agent Skill (Claude plugin source)
├── packages/skill-installer/ # @devlensio/skill — npx installer
├── bin/                      # npm launcher
├── npm/<platform>/           # 5 prebuilt binary packages
├── scripts/                  # Release tooling
└── server.json               # MCP registry manifest

The analysis engine lives in the separate devlensio package.

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DevLens Cloud

A hosted version is in development:

• Shareable graphs your whole team can access
• Cross-repo navigation — understand your entire org
• Give graphical context to AI agents for smarter code review and analysis
• No local setup required

Join the waitlist →