markusvankempen/mcp-server-inspector-chrome-extention

A Manifest V3 Chrome extension and VS Code extension for exploring, validating, and auditing Model Context Protocol (MCP) servers.
Author: Markus van Kempen
Research | Floor 7½ 🏢🤏
Topics: mcp · model-context-protocol · chrome-extension · vscode-extension · manifest-v3 · inspector · json-rpc · jsonschema · spec-compliance · llm-tools · ai-agents · developer-tools · devtools · sse · streamable-http
## Table of Contents
Overview
Features
Screenshots
Codebase Architecture & File Directory
Detailed API & Function Reference
Chrome Web Store Submission Package
Source Code & Access
Privacy
License
## Overview
The MCP Server Inspector & Spec Auditor is built for developers, AI engineers, and tool authors building and integrating Model Context Protocol servers. It provides automated specification compliance testing, deep JSONSchema Draft-07 validation on tool contracts, runtime health dry-runs, latency/token budgeting, and progressive disclosure group exploration.
## Features
3-tier specification audit with a 0–100% compliance score, covering lifecycle, JSON-RPC errors, tools, resources, prompts, and SEP extensions.
JSONSchema Draft-07 validation of every tool contract, plus SEP-1850 safety annotation checks.
Dynamic tool runner that builds type-safe forms from tool schemas and measures latency and token size.
Batch dry-run tests across all tools with schema health scoring.
README drift analyzer comparing GitHub README claims against live server discovery.
Progressive disclosure groups explorer (group/list, group/get) with token-savings estimates.
Raw JSON-RPC console with templates; Streamable HTTP and SSE support.
Zero runtime dependencies, no telemetry; settings are stored locally in chrome.storage.local.
## Screenshots
| Tool runner | Batch validation |
| README drift | Groups explorer |
| VS Code side panel | |
## Codebase Architecture & File Directory
mcp-server-inspector-chrome-extention/
├── src/ # Chrome extension (load THIS folder as "unpacked")
│ ├── manifest.json # Manifest V3 configuration
│ ├── background.js # Service worker (opens the full-tab workbench)
│ ├── workbench/ # Full-screen developer workbench
│ │ ├── index.html
│ │ ├── app.js # Main controller & UI orchestration
│ │ └── app.css
│ ├── popup/ # Compact toolbar popup
│ │ ├── popup.html
│ │ ├── popup.js
│ │ └── popup.css
│ ├── lib/ # Shared protocol logic
│ │ ├── mcp-client.js # JSON-RPC 2.0 / Streamable HTTP client & token estimator
│ │ └── spec-tester.js # Automated 3-tier specification & tool validation engine
│ ├── pages/
│ │ └── privacy.html # Extension privacy policy page
│ └── icons/ # Extension icons (16, 32, 48, 128 px)
├── vscode-extension/ # VS Code extension (same workbench UI in a webview)
│ ├── package.json # Extension manifest (command, settings)
│ ├── extension.js # Extension host: webview, HTTP, SecretStorage
│ ├── media/ # host-shim.js (webview host bridge), sidebar.{html,css,js} (Activity Bar panel), icons
│ └── webview/ # Generated: copy of src/workbench + src/lib (git-ignored)
├── test/ # Test tooling
│ ├── test-local-server.js # Mock MCP server with full SEP support (+ static host for src/)
│ ├── run-test-suite.js # Headless automated CLI verification runner