DevSnoop

Give your coding agent
eyes and hands

Inspect pages, interact with UI, capture logs, and verify your work visually — all through a Chrome extension that coding agents control directly.

Get Started View Docs

One HTTP call. Structured results.

Agents send JSON commands to localhost:9400 and get back compact, token-efficient responses. No raw HTML. No DevTools protocol.

request
curl -s -X POST http://127.0.0.1:9400/ \
  -H 'Content-Type: application/json' \
  -d '{"command":"page_summary","params":{"depth":3}}'
response
{
  "ok": true,
  "result": [
    {
      "tag": "header", "role": "banner",
      "interactiveElements": [
        { "tag": "a", "label": "Home", "selector": "nav a:nth-child(1)" },
        { "tag": "button", "label": "Sign In", "selector": "header button" }
      ]
    },
    {
      "tag": "main",
      "children": [
        { "tag": "form", "id": "search",
          "interactiveElements": [
            { "tag": "input", "type": "text", "selector": "#search input" },
            { "tag": "button", "label": "Search", "selector": "#search button" }
          ]
        }
      ]
    }
  ]
}

What your agent can do

Inspect

Semantic page structure, computed styles, element details — condensed for minimal token usage.

page_summaryinspect_elementfind

Interact

Click buttons, fill forms, scroll pages, hover elements. Your agent drives the browser like a user.

clickfillscrollhover

Debug

Console logs, network requests, JS exceptions — captured automatically, filtered on demand.

get_logsget_networkscreenshot

How it works

Coding Agent  ──HTTP──▸  Native Host  ──stdin──▸  Chrome  ──▸  Extension  ──▸  Page
                                         ◂──stdout──             ◂──            ◂──
                  ◂──JSON──
1

Agent sends a JSON command via HTTP to the native host running on localhost:9400.

2

Native host forwards the command to Chrome via Native Messaging. The extension executes it on the page.

3

Structured, token-efficient results flow back the same path. No raw HTML — just what the agent needs.

Works with any coding agent

Any tool that can make HTTP requests can control the browser.

Claude CodeCursorWindsurfClineAiderAny agent with HTTP access

Ready to give your agent
superpowers?

Get DevSnoop