kuri-server

name	kuri-server
description	Use kuri-server to automate Chrome via HTTP API — navigate pages, get a11y snapshots, interact with elements, capture network traffic (HAR), extract cookies, and bypass bot protection. Use when the user wants to browse websites, scrape data, fill forms, test web apps, or interact with protected sites via a headless browser. Trigger phrases include "browse to", "open the page", "get the page content", "fill the form", "capture network traffic", "get cookies", "bypass bot protection".
argument-hint	[endpoint] [params]
allowed-tools	Bash

kuri — HTTP API Browser Automation Server

kuri is a CDP automation server. It launches Chrome, connects via WebSocket, and exposes an HTTP API for browser control. Zero Node.js, single binary.

Starting the server

# Default — launches headless Chrome, listens on :8080
./zig-out/bin/kuri

# Visible Chrome (for debugging)
HEADLESS=false ./zig-out/bin/kuri

# With residential proxy (for bot-protected sites)
KURI_PROXY=socks5://user:pass@proxy:1080 ./zig-out/bin/kuri

# Connect to existing Chrome
CDP_URL=ws://127.0.0.1:9222/devtools/browser/... ./zig-out/bin/kuri

Core workflow

Prefer the session-first loop: tab/new → page/info → snapshot → act → repeat

BASE=http://127.0.0.1:8080
SESSION=agent-demo

# 1. Create or switch into a session-scoped tab
curl -s -H "X-Kuri-Session: $SESSION" \
  "$BASE/tab/new?url=https%3A%2F%2Fexample.com"

# 2. Read live page info
curl -s -H "X-Kuri-Session: $SESSION" "$BASE/page/info"
# → {"tab_id":"ABC123","url":"https://example.com/","title":"Example Domain",...}

# 3. Snapshot (a11y tree with element refs)
curl -s -H "X-Kuri-Session: $SESSION" "$BASE/snapshot?filter=interactive&format=compact"
# → [{"ref":"e0","role":"heading","name":"Example Domain"},
#    {"ref":"e1","role":"link","name":"More information..."}]

# 4. Interact via refs
curl -s -H "X-Kuri-Session: $SESSION" "$BASE/action?ref=e1&action=click"
curl -s -H "X-Kuri-Session: $SESSION" "$BASE/action?ref=e2&action=fill&value=hello"

# 5. Read results
curl -s -H "X-Kuri-Session: $SESSION" "$BASE/page/info"
curl -s -H "X-Kuri-Session: $SESSION" "$BASE/snapshot?filter=interactive&format=compact"

If you already know a tab id, set it directly with:

curl -s -H "X-Kuri-Session: $SESSION" "$BASE/tab/current?tab_id=ABC123"

Choosing the right Kuri browser path

Use the main kuri server for production browser automation. It drives Chrome/CDP and exposes HTTP sessions, page info, snapshots, actions, HAR, cookies, and screenshots.

Use the separate kuri-browser/ workspace only for the experimental Zig-native browser runtime. It is not wired into the root build and cannot replace headless Chrome yet.

cd kuri-browser
zig build run -- render https://news.ycombinator.com --selector ".titleline a" --dump text
zig build run -- render https://todomvc.com/examples/react/dist/ --js --wait-eval "document.querySelectorAll('.todo-list li').length >= 1"
zig build run -- bench --offline
zig build run -- parity --offline
zig build run -- serve-cdp --port 9333

serve-cdp exposes Chrome-style HTTP discovery plus a minimal WebSocket JSON-RPC router. It can answer basic Browser/Target/Page/Runtime/DOM methods, and Runtime.evaluate returns V8-shaped CDP remote objects backed by QuickJS. This is useful for protocol smoke tests, but it is not broad Playwright/Puppeteer compatibility and cannot replace Chrome yet.

For screenshots, kuri-browser currently delegates to the main Kuri/CDP renderer:

# terminal 1, repo root
zig build
./zig-out/bin/kuri

# terminal 2
cd kuri-browser
zig build run -- screenshot https://example.com --out example.jpg --compress --kuri-base http://127.0.0.1:8080

--compress captures a PNG baseline and JPEG candidate, writes the smaller file, and reports byte savings. Current local measurement on https://example.com: 20,523 bytes PNG to 18,183 bytes JPEG quality 50, saving 2,340 bytes or 11%.

Key endpoints

Navigation & page control

Endpoint	Description
GET /tab/current	Get or set the current tab for an X-Kuri-Session
GET /page/info	Get live URL, title, ready state, viewport, and scroll
GET /navigate?tab_id=X&url=URL	Navigate to URL (auto bot-detection)
GET /navigate?...&bot_detect=false	Navigate without bot check (faster)
GET /back?tab_id=X	Browser back
GET /forward?tab_id=X	Browser forward
GET /reload?tab_id=X	Reload page
GET /wait?tab_id=X&selector=CSS	Wait for element to appear
GET /stop?tab_id=X	Stop page loading

Reading the page

Endpoint	Description
GET /snapshot?tab_id=X&filter=interactive&format=compact	Lowest-token interactive a11y refs (best for agents)
GET /snapshot?tab_id=X&filter=interactive	Only interactive elements as JSON
GET /diff/snapshot?tab_id=X	Changes since last snapshot
GET /text?tab_id=X	Page text content
GET /evaluate?tab_id=X&expression=JS	Run JavaScript
GET /screenshot?tab_id=X	Base64 screenshot
GET /markdown?tab_id=X	Page as markdown
GET /links?tab_id=X	All hyperlinks
GET /get?tab_id=X&type=title	Get title/url/html/text/value

Interacting

Endpoint	Description
GET /action?tab_id=X&ref=eN&action=click	Click element
GET /action?tab_id=X&ref=eN&action=fill&value=V	Fill input field
GET /action?tab_id=X&ref=eN&action=select&value=V	Select option
GET /action?tab_id=X&ref=eN&action=hover	Hover element
GET /action?tab_id=X&ref=eN&action=focus	Focus element
GET /keyboard/type?tab_id=X&text=hello	Type text
GET /keydown?tab_id=X&key=Enter	Press key
GET /scrollintoview?tab_id=X&ref=eN	Scroll to element
GET /drag?tab_id=X&src=eN&tgt=eM	Drag and drop

Network & cookies

Endpoint	Description
GET /cookies?tab_id=X	Get all cookies
GET /cookies/set?tab_id=X	Set cookies (POST body)
GET /cookies/delete?tab_id=X&name=N	Delete cookie
GET /headers?tab_id=X	Set extra HTTP headers (POST body)
GET /har/start?tab_id=X	Start recording network traffic
GET /har/stop?tab_id=X	Stop + get HAR JSON
GET /har/replay?tab_id=X&filter=api&format=all	Get API map with code snippets
GET /har/status?tab_id=X	Check recording status

Bot protection

Endpoint	Description
GET /navigate?...&bot_detect=true	Auto-detect blocks (default)
Response when blocked	{"blocked":true,"blocker":"akamai","fallback":{"suggestions":[...]}}
Stealth	Auto-applied on startup (UA rotation, webdriver hide, WebGL/canvas spoof)
Proxy	Set KURI_PROXY=socks5://... env var

HAR replay workflow (bypass browser for API calls)

When browser interaction is flaky or you want to call APIs directly:

# 1. Start recording
curl -s "$BASE/har/start?tab_id=ABC123"

# 2. Navigate and let the page load
curl -s "$BASE/navigate?tab_id=ABC123&url=https://target.com&bot_detect=false"
sleep 8

# 3. Get API map with code snippets
curl -s "$BASE/har/replay?tab_id=ABC123&filter=api&format=curl"
# → {"api_calls":[
#     {"method":"POST","url":"https://target.com/api/v4/data",
#      "request_headers":"{\"Cookie\":\"...\",\"X-CSRFToken\":\"...\"}",
#      "post_data":"{\"query\":\"...\"}",
#      "curl":"curl -X POST 'https://target.com/api/v4/data'"}
#   ]}

# 4. Grab cookies for direct API calls
curl -s "$BASE/cookies?tab_id=ABC123"

# 5. Call APIs directly with captured cookies + headers
curl -s 'https://target.com/api/v4/data' \
  -H 'Cookie: session=abc; csrf=xyz' \
  -H 'X-CSRFToken: xyz'

Tips for agents

1. Prefer session headers — set X-Kuri-Session and let the server remember the current tab.
2. Use /page/info between steps — it is the cheapest live state check for URL/title/ready state.
3. Use compact interactive snapshots — filter=interactive&format=compact gives refs like e0, e1 plus useful state such as checked=false, disabled, or expanded=false at lower token cost.
4. Bot detection is automatic — if navigate returns {"blocked":true}, read the fallback.suggestions.
5. HAR for API discovery — start HAR before navigating, then use /har/replay?filter=api to find the site's API endpoints.
6. Cookies transfer — use /cookies to get browser session cookies, then make direct curl calls.
7. Refs persist per snapshot only — take a new snapshot after any navigation or meaningful DOM change.
8. Native browser experiment is separate — kuri-browser is useful for parity work and benchmarks. Its serve-cdp router is minimal, screenshots still use the Kuri/CDP fallback, and native layout/paint is not implemented.