Tool Index: one local MCP server that gives an agent hundreds of tools through three
An open-source gateway with three tools (search, describe, call) over all your MCP servers. Power users and small teams pay for synced configs.
Crowded · 8,200-tool gateway paper plus GatewayBench
Written for: Solo builder
Next step
This week, build the three-tool stdio server over the MCP servers in your own Claude Desktop config. Run GatewayBench against it and put the score in the README. Launch on r/mcp and Show HN with the score table.
Why now
Developers who stack ten or more MCP servers are running out of context and getting worse tool choices. A paper now shows the three-tool pattern working in production, and GatewayBench gives you a public score to put on the README. The HN thread asking 'how do you know what's going on without your own LLM proxy' and the Rust gateway antirion show people are already building gateways. This space is crowded: Docker's and MetaMCP's gateways exist and labs are adding tool search natively. The opening is local, works across any client, and comes with a published GatewayBench score.
What became possible
The Tool Recommendation paper describes a deployed gateway that gives agents about 8,200 tools, whose definitions together exceed any model's context window, through a fixed set of three tools. It targets the failure where a multi-step task breaks because one needed tool was never loaded. GatewayBench is the first benchmark that scores MCP gateways on both capability and security.
Two ways in
- toolindex
A stdio MCP server that reads your existing client configs and embeds every tool definition. It exposes search_tools, describe_tool and call_tool, logs every call and filters tool descriptions for injected instructions before the agent sees them.
- Customer
- Developers running Claude Code, Cursor or VS Code with many MCP servers
- Model
- Free open-source binary. $10 a month for synced config across machines and shared team allow-lists
- Gateway scoreboard
Run GatewayBench against popular open-source MCP gateways and publish the results, including your own. It doubles as marketing and an honest comparison.
- Customer
- Developers choosing a gateway
- Model
- Free. Brings users to toolindex
Competition
The remaining room is narrow. One option is a zero-config drop-in that auto-imports existing Cursor, VS Code and Claude configs, shows measurably better retrieval accuracy than native Tool Search, and adds TOFU pinning of tool descriptions plus readable call logs. That could still find users in Cursor and VS Code if those clients lack strong native deferral, but it is a feature rather than a business. The scoreboard is the more defensible wedge. No benchmark named GatewayBench turned up, and the existing comparisons are mostly vendor-authored (Maxim, MikkoParkkola) or cover only a few gateways (AIMultiple), so a reproducible open benchmark that tests tool-retrieval accuracy at hundreds of tools, token cost and injection resistance could become a reference. Monetizing it would be hard, and including your own gateway would undercut its credibility unless the methodology is fully open.
Full competition notes (11 competitors)
The core idea, a local gateway exposing search, describe and call over all your MCP servers, is already built several times. At least five open-source projects use nearly the same meta-tool design. Claude Code now defers MCP tools natively through Tool Search, which takes away much of the need for the most important target client. Description filtering is covered by Snyk Agent Scan and several guard proxies. Config sync already exists as free CLIs and git-checked .mcp.json files, so the proposed paid tier has little to charge for. The remaining room is narrow. One option is a zero-config drop-in that auto-imports existing Cursor, VS Code and Claude configs, shows measurably better retrieval accuracy than native Tool Search, and adds TOFU pinning of tool descriptions plus readable call logs. That could still find users in Cursor and VS Code if those clients lack strong native deferral, but it is a feature rather than a business. The scoreboard is the more defensible wedge. No benchmark named GatewayBench turned up, and the existing comparisons are mostly vendor-authored (Maxim, MikkoParkkola) or cover only a few gateways (AIMultiple), so a reproducible open benchmark that tests tool-retrieval accuracy at hundreds of tools, token cost and injection resistance could become a reference. Monetizing it would be hard, and including your own gateway would undercut its credibility unless the methodology is fully open.
- Claude Code MCP Tool Search (Anthropic)
Built into Claude Code. It defers MCP tool definitions and gives the model a search tool that loads them on demand. This removes the main pain for the biggest target client. The Anthropic API also supports defer_loading with a tool search tool.
- MCP Gateway (MikkoParkkola)
Open-source meta-MCP mode with four meta-tools, including gateway_search_tools and gateway_invoke, over many backend servers. It publishes its own BENCHMARKS.md.
- MCP Gateway (eznix86)
Open-source gateway that offers unified search, describe and invoke across multiple servers and exposes only 5 tools. It is almost exactly the proposed design.
- meta-mcp (Stacklok ToolHive)
Hybrid semantic and keyword search across connected servers, then routes the chosen call through the meta server. Backed by a funded company.
- MCP of MCPs
Meta-server that merges all MCP servers into one endpoint and adds a semantic search tool.
- Klavis Strata
YC-backed, Apache 2.0. Progressive tool discovery runs servers, then categories, then actions, then schemas, and full schemas load only when a tool is executed. It reports MCPMark benchmark gains, which are vendor claims.
- Bifrost (Maxim AI)
Gateway whose Code Mode reportedly cuts input tokens by up to 92.8% at 508 tools. Maxim also publishes its own gateway comparison, the same marketing-by-comparison approach the scoreboard idea proposes.
- awesome-mcp-gateways (e2b)
Curated list of many gateways, including MetaMCP, Docker MCP Gateway, agentgateway, mcpproxy-go and AIRIS MCP Gateway (seven meta-tools). It shows how saturated the category is.
- Snyk Agent Scan (formerly MCP-Scan)
The most widely adopted scanner for tool poisoning, prompt injection in tool descriptions, and rug pulls. It covers the injected-instruction filtering feature.
- AIMultiple MCP gateway benchmark
Independent benchmark, updated August 2026, of six gateways on latency, per-tool permissions, injection blocking and audit completeness. It already fills much of the honest-scoreboard niche.
- mcp-sync (ztripez)
Free CLI that syncs MCP configs across Claude Code, Cursor, VS Code, Cline and others. Project .mcp.json files in git already share configs within teams, which weakens the paid synced-config tier.
Checked 2026-10-19
Risks
- Clients and labs are building native tool search, which could make this redundant within months.
- A gateway becomes a single point where prompt injection and credential theft concentrate.
- There is a crowded field of free MCP gateways, and the pull for paid tiers is weak.
Strong team fit and buildability; open space is the weak point (3).
tech 7 · pull 6 · space 3 · fit 8 · build 8
Exposed
Companies that could benefit or be threatened. News and context, not investment advice.
Momentum of its main topic
Sources
Status history
- 2026-10-19 Flagged as buildable