A browser built to be driven by an AI β the perception and action layer that gives an agent
fast, complete, verifiable control of the web. Ships on npm as ecobrowser: a TypeScript library and an MCP server in one package.
Structured (no-pixel) perception Β· verified self-healing actions Β· incremental diff perception Β· a live view to watch it work.
- What is this?
- Highlights
- Architecture
- How it works
- Quick start
- MCP tools
- How it compares
- Configuration
- Scripts
- Project layout
- Security & scope
- Roadmap
Most "AI browsers" are one of two things: a chat sidebar bolted onto a browser, or a headless scraping API with no feedback loop. This is neither. It's the layer that makes a real browser usable by a model β the primary "user" is an AI, and a human just supervises.
It gives an agent a compact, structured view of a page (an addressable list of interactive elements, not a screenshot), lets it act on those elements by stable id, tells it whether each action actually worked, and streams the whole thing to a live view a human can watch. It's model-agnostic and downloadable β not tied to one vendor's extension.
The design principle, everywhere: do work in code so the model doesn't spend tokens and reasoning on it β verifying outcomes, diffing pages, recovering from failures, finding elements.
β οΈ Scope & honesty. This is a fast, local, single-user developer tool, built to be pointed at your own or authorized sites. It's young β thoroughly tested on its own paths, but not battle-hardened across thousands of real websites the way mature tools are. See Security & scope.
| ποΈ Structured perception | The AI sees a compact list of interactive elements with stable ids β no screenshotβvision round-trip. |
| π― Act by id | Click/type/select by e3, never by guessed CSS selectors or pixel coordinates. |
| β Verified actions | Every action returns did it work and did the page change β success / silent no-op / failure, not a guess. |
| π©Ή Self-healing | If an element's id moved (page re-rendered), it re-locates the element by identity and retries. |
| π Durable ids | An element keeps its id across snapshots, so the AI can reference something it saw steps ago. |
| β‘ Incremental perception | changes() returns only the delta; snapshots are cached until the DOM actually changes. |
π find(description) |
Ask for "the search box" and get just the match β not a whole-page dump. |
| π First-class debugging | Console logs, page errors, and network requests captured β errors scoped to the action that caused them. |
| π₯οΈ Live view | Watch a headless run in your browser β refreshing screenshot + colour-coded action trace. |
| π MCP + npm | One engine, two front doors: an MCP server (zero-code) and a typed TypeScript library. |
flowchart TD
AI["π€ AI client<br/>Claude Desktop Β· Cursor Β· your agent"]
MCP["<b>mcp.ts</b><br/>MCP server Β· 13 tools"]
LIVE["<b>live.ts</b><br/>live-view server"]
ENGINE["<b>browser.ts</b><br/>AIBrowser / AIPage<br/><i>the whole product</i>"]
CHROME["Chromium<br/>(headless by default)"]
HUMAN["π§ human<br/>watches & supervises"]
AI -- "JSON-RPC 2.0 / stdio" --> MCP
MCP -- "method calls" --> ENGINE
ENGINE -- "Chrome DevTools Protocol" --> CHROME
ENGINE -- "events + frames" --> LIVE
LIVE -- "screenshot + action trace" --> HUMAN
classDef eng fill:#6E56CF,stroke:#4C3A9E,color:#fff;
classDef srv fill:#1e2a3a,stroke:#89b4fa,color:#cdd6f4;
class ENGINE eng;
class MCP,LIVE srv;
One engine, two front doors. All the real logic lives in browser.ts. mcp.ts is a thin adapter that exposes the engine's methods as protocol tools; live.ts is a read-only window for a human. The same engine could be wrapped as a CLI or REST API β MCP is just one adapter.
flowchart LR
A["act by id<br/>(click / type / select)"] --> B{"element<br/>found?"}
B -- yes --> C["smart-wait<br/>+ act"]
B -- "no Β· id moved" --> H["π©Ή self-heal:<br/>re-locate by identity"]
H --> C
C --> D{"effect<br/>verified?"}
D -- yes --> OK["β
ActionResult<br/>ok Β· changed?"]
D -- "no Β· error" --> R{"retries<br/>left?"}
R -- yes --> C
R -- no --> F["β οΈ ActionResult<br/>fail + heal hint"]
classDef ok fill:#1e3a2e,stroke:#a6e3a1,color:#a6e3a1;
classDef bad fill:#3a1e26,stroke:#f38ba8,color:#f38ba8;
class OK ok;
class F bad;
Perception runs a script inside the page that collects interactive elements, stamps each with a durable data-ai-id, and captures role / name / value / state. A MutationObserver tracks a DOM version, so unchanged snapshots are served from cache and changes() can return just the delta.
sequenceDiagram
participant AI as π€ AI client
participant S as mcp.ts (server)
participant E as browser.ts (engine)
AI->>S: initialize
S-->>AI: capabilities
AI->>S: tools/list
S-->>AI: 13 tools + JSON schemas
Note over AI: the model now knows what it can do
AI->>S: tools/call Β· browser_navigate {url}
S->>E: goto() + snapshot()
E-->>S: structured elements
S-->>AI: content:[ text ]
AI->>S: tools/call Β· browser_click {id}
S->>E: clickById() β verify β heal
E-->>S: ActionResult + delta
S-->>AI: content:[ text ]
It's an MCP server because it registers schema-typed tools and answers initialize / tools/list / tools/call as JSON-RPC 2.0 over stdio β the browser control is just what those tools happen to do.
Prerequisites: Node.js 18+.
npm install ecobrowserChromium is downloaded automatically on install (a postinstall hook). If you
install with --ignore-scripts, fetch it manually: npx playwright install chromium.
Claude Desktop β add to claude_desktop_config.json:
{
"mcpServers": {
"ecobrowser": {
"command": "npx",
"args": ["-y", "ecobrowser-mcp"],
"env": { "AI_BROWSER_HEADED": "1" }
}
}
}Claude Code:
claude mcp add ecobrowser -- npx -y ecobrowser-mcpRestart the client, then just ask: "navigate to example.com and list the links."
Run npx ecobrowser-mcp --help for setup, the full tool list, and environment variables.
(Working from a clone instead of the published package? Point the client at the source directly: npx tsx <repo>/src/mcp.ts.)
import { AIBrowser } from "ecobrowser";
const browser = await AIBrowser.launch({ headless: true });
const page = await browser.newPage();
await page.goto("https://example.com");
const snap = await page.snapshot(); // { url, title, elements: [{ id, tag, role, name, value?, state? }] }
const [search] = await page.find("search box");
const result = await page.clickById(snap.elements[0].id);
console.log(result.detail); // "click e0 succeeded (page changed)."
const diff = await page.changes(); // { added, removed, changed, unchanged }
console.log(page.console(), page.network()); // first-class debugging
await browser.close();The server exposes 13 tools; an MCP client discovers them (name + JSON schema) via tools/list.
| Tool | What it does |
|---|---|
browser_navigate |
Open a URL, return a structured snapshot. |
browser_snapshot |
Structured snapshot of the current page (cached until it changes). |
browser_changes |
Only what changed since your last snapshot β cheap re-perception. |
browser_find |
Find interactive elements matching a description; get just the matches. |
browser_read_text |
Visible text of the page. |
browser_back |
Go back in history. |
browser_click |
Click an element by id (verified, self-healing); returns the delta. |
browser_type |
Type into a field by id (verifies the value landed). |
browser_console |
Console logs + page errors on the current page. |
browser_network |
Network responses (status, method, url). |
browser_evaluate |
Run a JS expression in the page, return the result. |
browser_extract_links |
All links as name/href pairs. |
browser_reset |
Discard the session; the next action starts fresh (crash recovery). |
Head-to-head vs Playwright MCP on the same page (npm run bench), measuring bytes returned to the model and tool latency.
Full page snapshot β smaller is better
This framework ββββββββββββββββββββββββ 41 KB (~10K tokens)
Playwright MCP ββββββββββββββββββββββββ 128 KB (~32K tokens)
Re-perceive latency β smaller is better
This framework β 5 ms (cache hit)
Playwright MCP ββββββββββββββββββββββββ 150 ms (re-serializes every time)
Incremental re-perceive after an action
This framework β delta only (bytes)
Playwright MCP ββββββββββββββββββββββββ full page again (no diff primitive)
Honest caveats. This measures perception payload + tool latency, not end-to-end LLM wall-clock (no live model ran). Part of the size gap is scope β we capture interactive elements only, Playwright MCP captures the full accessibility tree. And we're faster than Playwright MCP (the wrapper), not Playwright (the shared engine under both) β the wins are caching, diffing, and a leaner format, all ideas a competitor could adopt.
| Env var | Effect |
|---|---|
AI_BROWSER_HEADED=1 |
Show the native browser window (default: headless). |
AI_BROWSER_LIVE=0 |
Disable the live-view server. |
AI_BROWSER_LIVE_PORT=N |
Preferred live-view port (default 7333, steps to the next free port if busy). |
AI_BROWSER_ALLOW_LOCAL=1 |
Allow file:// / privileged-scheme navigation (blocked by default). |
Live view: when the MCP server starts it also serves a loopback-only page (default http://localhost:7333) β a refreshing screenshot plus a colour-coded action trace β so you can watch a headless run.
npm test # unit tests (diff, find, state, url-guard) β no browser needed
npm run build # compile the publishable package to dist/ (library + MCP bin)
npm run typecheck # tsc --noEmit over everything, dev scripts included
npm run demo # exercises the engine directly (headed; AI_BROWSER_HEADED=0 for headless)
npm run smoke # spawns the MCP server as a real MCP client and drives it
npm run live # starts the live view and verifies its endpoints
npm run bench # head-to-head vs Playwright MCP
npm run mcp # run the MCP server on stdioBenchmark note: Playwright MCP is a
devDependency; install its browser once withnpx @playwright/mcp install-browser chrome-for-testingbeforenpm run bench.
src/
index.ts # public package entry β re-exports the engine + LiveView
browser.ts # the core engine β AIBrowser / AIPage (this is the whole product)
mcp.ts # MCP server: registers the engine's methods as 13 tools (the ecobrowser-mcp bin)
live.ts # live-view server (screenshot + action trace)
demo.ts # in-code engine demo (5 parts, incl. self-healing)
mcp-smoke.ts # end-to-end MCP client test
live-smoke.ts # live-view endpoint test
bench-h2h.ts # head-to-head benchmark vs Playwright MCP
test.ts # unit tests for the pure logic
tsconfig.build.json # build config β compiles only the public surface to dist/
SPEC.md # full technical specification, north star, roadmap
Only dist/ (plus README, SPEC, LICENSE) ships in the npm tarball β the dev scripts stay in the repo.
Because it's a downloadable tool you run yourself, how it's used is your responsibility. Built-in guards:
- Loopback-only live view β never exposed to the LAN; the trace is rendered XSS-safely (
textContent, neverinnerHTML). - Navigation guard β
file://,chrome://,javascript:and other privileged schemes blocked by default (AI_BROWSER_ALLOW_LOCAL=1to opt out). - Bounded & recoverable β capped logs, per-tool timeouts, automatic crash recovery, graceful shutdown, port fallback.
Deliberately not in scope: multi-tenant hosting, auth/session isolation between users, or sandboxing browser_evaluate (which runs arbitrary JS in the page β appropriate only for sites you trust). Point it at your own or authorized sites.
flowchart LR
M0["M0 Β· spike"] --> M1["M1 Β· engine"] --> REL["reliability<br/>+ self-heal"] --> M3["M3 Β· MCP"] --> M4["M4 Β· speed"] --> M5["M5 Β· live view"] --> AIF["AI-friendliness"] --> HARD["hardening"] --> M2["M2 Β· npm<br/>package"] --> M6["M6 Β· auth/proxy<br/>(BYO) π¦ next"]
classDef done fill:#1e3a2e,stroke:#a6e3a1,color:#a6e3a1;
classDef next fill:#3a2e1e,stroke:#f9e2af,color:#f9e2af;
class M0,M1,REL,M3,M4,M5,AIF,HARD,M2 done;
class M6 next;
Built and tested: the engine, reliability + self-healing, the MCP server, caching + diff perception, the live view, the AI-friendliness pass, the hardening pass, and the npm package (ecobrowser, with the ecobrowser-mcp bin).
Next β M6: opt-in, BYO-key auth/proxy/CAPTCHA for authorized sites.
See SPEC.md for the full specification and north star.
Built by Haidar Esber β Lebanese software & web developer based in France.