Blog | Gasoline Agentic Devtools

Gasoline v5.2.1 Released

Jan 10, 2026

Brenn Hill

What’s New in v5.2.1

Quick patch release fixing issues with error clustering in v5.2.0.

Fixes

Fixed error clustering not deduplicating similar stack frames
Resolved network filter persistence across tab navigation
Improved WebSocket connection tracking stability

Upgrade

npm install -g gasoline-mcp@5.2.1

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v5.2.1 Release

Gasoline v5.2.0 Released

Jan 10, 2026

Brenn Hill

What’s New in v5.2.0

Gasoline v5.2.0 improves error handling, network inspection, and adds better filtering options for high-volume environments.

Features

Enhanced Error Clustering — Group related errors for clearer debugging
Network Filtering — Filter requests by status, content-type, and size
Better Error Context — Stack traces and request/response details inline
Performance Improvements — Reduced memory usage on long-running sessions

Improvements

Error deduplication across similar stack traces
Network waterfall visualization improvements
Better handling of WebSocket connections
Improved timeout handling for slow networks

Upgrade

npm install -g gasoline-mcp@5.2.0

Full Changelog

v5.2.0 Release

Gasoline v5.0.0 Released

Jan 4, 2026

Brenn Hill

What’s New in v5.0.0

Gasoline v5.0.0 marks the initial public release of the Gasoline MCP protocol and extension. This release includes core browser observability features for AI coding assistants.

Features

Browser Telemetry Capture — Real-time streaming of console logs, network requests, and exceptions
MCP Protocol Integration — Compatible with Claude Code, Cursor, Copilot, and other MCP clients
4-Tool Interface — observe, generate, configure, interact tools for full-stack automation
Zero Dependencies — Lightweight Go binary with no external service requirements

Capabilities

Real-time log and error capture
Network request/response inspection
Page interaction and automation
CSS-based element highlighting
Form filling and submission automation

Get Started

npm install -g gasoline-mcp
gasoline-mcp --help

Install the browser extension from the Chrome Web Store or load it manually via Developer Mode.

Full Changelog

v5.0.0 Release

Gasoline v4.0.0 Released

Dec 22, 2025

Brenn Hill

What’s New in v4.0.0

Gasoline v4.0.0 is the refinement phase. The core architecture from v3 works well—this version focuses on making it robust and adding missing developer-focused features.

Major Features

User Action Recording — Record clicks, typing, navigation with smart selectors
Web Vitals Capture — LCP, CLS, INP, FCP tracking
API Schema Inference — Auto-detect OpenAPI patterns from network traffic
Error Aggregation — Group and deduplicate similar errors
Session Checkpoints — Save browser state, diff changes, detect regressions

Performance

Optimized ring buffers — 2000-event cap prevents unbounded memory growth
Efficient filtering — Skip irrelevant logs (ads, tracking, etc.)
Smart deduplication — Collapse repeated identical events
Rate limiting — Respect browser and extension quotas

Developer Experience

Better error messages — Clear explanations of what went wrong and why
Command-line flags — --port, --server, --api-key for flexibility
Health check endpoint — /health for verifying setup
Example integration — Claude Code, Cursor, Copilot configs included

Stability

Comprehensive testing — 80+ unit and integration tests
Error recovery — Graceful handling of extension crashes/restarts
Logging improvements — Debug mode for troubleshooting
TypeScript strict mode — Zero implicit any

Known Limitations

Recording still in alpha (no video yet)
No Safari/Firefox support (MV3 requirement)
Replay system not yet implemented
Limited to Chrome 120+

Status: This version proved the concept could handle real-world usage. Ready for broader testing.

Next: Production-grade recording system, broader browser support research, performance benchmarking.

See [GitHub](https://github.com/brennhill/gasoline-agentic-browser-devtools-mcp for source.

Gasoline v3.0.0 Released

Dec 19, 2025

Brenn Hill

What’s New in v3.0.0

Gasoline v3.0.0 replaces the HTTP polling disaster with a proper MCP stdio server. This was the breakthrough version.

Major Changes

Stdio-based MCP Server — Proper bidirectional JSON-RPC 2.0 over stdio
Real-time streaming — Events stream immediately, no polling
All 4 tools implemented — observe(), generate(), configure(), interact()
Event types — Console logs, network requests, WebSocket messages, exceptions

Features

Console Logs — Full argument capture, log levels
Network Capture — Request/response bodies, headers, status codes
WebSocket Events — Message payloads and connection lifecycle
Exceptions — Stack traces and error context
User Actions — Click/type/navigate event recording
Persistence — Logs survive server restart (SQLite backend)

Architecture

Extension → Go daemon (localhost HTTP)
Daemon ↔ MCP client (stdio, bidirectional)
Ring buffer for event history
Persistent storage for audit trail

Performance

<100ms latency for event delivery
Concurrent clients — Multiple AI tools can connect simultaneously
Low memory — Circular buffer limits are enforced
Zero external deps — Pure Go stdlib

Known Limitations

Chrome-only — Manifest V3 requirement
Local network only — Binds to 127.0.0.1
No replay — Can’t scrub through history yet
Recording not yet implemented

Milestone: This was the version that proved the concept could work. Everything from here builds on this foundation.

See [GitHub](https://github.com/brennhill/gasoline-agentic-browser-devtools-mcp for source.