Gasoline v5.8.0 Released

Feb 6, 2026

Brenn Hill

What’s New in v5.8.0

Gasoline v5.8.0 solves a long-standing WebSocket capture blind spot: pages that create WebSocket connections before the inject script loads now have those connections captured automatically. This release also adds visual feedback for AI actions and ships a comprehensive 106-test UAT suite.

Features

Early-patch WebSocket capture — A new world: "MAIN" content script patches window.WebSocket before any page JavaScript runs. This means sites like Binance that create WebSocket connections immediately on page load now have those connections captured and visible via observe(websocket_status). Buffered connections are seamlessly adopted when the full inject script initializes.
Visual action toasts — When AI tools use interact() to navigate, execute JavaScript, or highlight elements, a brief toast overlay appears on the page showing what the AI is doing. This makes AI actions visible to developers watching the browser.

Fixes

Fixed camelCase to snake_case field mapping for network waterfall entries (duration, transfer_size, etc.)
Command results now route through the /sync endpoint with proper client ID filtering
After navigation, tracking state is broadcast so favicon updates correctly
Empty arrays return [] instead of null in JSON responses
Bridge timeouts now return a proper extension_timeout error code

Testing

106-test parallel UAT suite replacing the previous 8-test script, covering observe, generate, configure, interact, and data pipeline categories
16-test human smoke test with error clusters, DOM query, full form lifecycle, highlight, and real WebSocket traffic tests
All tests default to fail (not pass) with strict field validation throughout

Performance

Binary sizes decreased ~4% from v5.7.5. All SLOs continue to pass:

MCP fast-start: ~130ms
Tool response: < 1ms
Max binary: 7.7 MB (target: < 15 MB)

Upgrade

npx gasoline-mcp@5.8.0

Full Changelog

v5.7.5…v5.8.0