feat: Claude Desktop Extension (.mcpb) for one-click install

[zoharbabin]

Why

Non-developer users (researchers, analysts, legal professionals, journalists, students) are our largest potential audience but most cannot install MCP servers via command line. Anthropic created Desktop Extensions (.mcpb format) specifically to solve this.

Current state

A manifest file already exists at mcpb/manifest.json (version 0.3) with:

• Server type: binary
• User config schema: Google CSE keys, search provider, Brave key
• All 8 tools declared

What's missing: The actual build pipeline to package platform-specific binaries into distributable .mcpb files, and registration in Claude's extension directory.

Remaining work

1. Build pipeline — Add a GoReleaser or Makefile target that packages the Go binary + manifest into a .mcpb file for each platform (macOS arm64/amd64, Windows amd64, Linux amd64)
2. Manifest refinements:
   • Update required: true on Google keys to required: false (since Brave/SearXNG work without them)
   • Add SEARCH_ROUTING and additional provider keys to config schema
   • Version should match release tag (not 0.0.0-template)
3. Distribution:
   • Include .mcpb files in GitHub Releases (alongside the existing tar.gz archives)
   • Register in Claude's extension directory for discovery
   • Add "Download Extension" button/link prominently in README
4. User experience:
   • Ensure the one-click install flow works end-to-end on macOS and Windows
   • Test API key entry flow via OS keychain
   • Add a "Getting Started" screen or link after install

Impact

This is the single highest-impact change for reaching non-developer users. A researcher using Claude Desktop should be able to add our research tools in under 60 seconds without touching a terminal.

Competitive context

• Perplexity MCP uses npx (requires Node.js — developer tool)
• Exa MCP uses npx (same barrier)
• Brave Search MCP uses npx (same barrier)
• A .mcpb makes us the EASIEST research MCP to install for non-developers

[zoharbabin]

Resolved — the full .mcpb distribution pipeline is complete:

Build pipeline (already done):

• scripts/build-mcpb.sh builds platform-specific .mcpb bundles (macOS arm64/amd64, Linux amd64/arm64, Windows amd64)
• Bundles uploaded to GitHub Releases on every tagged release

Manifest refinements (done in 145460e):

• Google API keys now required: false (server works with Brave, SearXNG, and other providers)

Distribution automation (done in 145460e):

• Official MCP Registry: auto-publishes on release via mcp-publisher + GitHub OIDC (zero secrets)
• Smithery.ai: auto-publishes on release via REST API
• Cline Marketplace: llms-install.md + 400x400 logo ready for submission
• Glama.ai: already listed (auto-indexes from MCP Registry)

User experience (done in 145460e):

• Claude Code plugin (.claude-plugin/) with SessionStart hook that auto-downloads the correct binary
• One-click install via /plugin install web-researcher-mcp once submitted to the community marketplace
• llms-install.md for AI-agent-guided setup in Cline and other tools