An agent-callable MCP discovery tool is one an AI agent queries directly, inside the same tool call it already uses to find a capability it lacks, rather than a website a developer browses by hand and copy-pastes an install command from. That distinction matters more than raw catalog size: Glama’s own counter shows nearly 90,000 indexed servers and Smithery’s registry lists over 22,000, but neither number tells you whether an agent can act on a result without a human relaying it back and forth.
The seven tools in this report split cleanly into two groups. MCPfinder, the Official MCP Registry and PulseMCP are built primarily as discovery layers: they find and describe servers, and in MCPfinder’s case generate a ready-to-use client config, then step back. Smithery, Composio and Klavis AI go further, pairing discovery with a managed or self-hostable gateway that also authenticates and executes the tools an agent finds. Glama sits in between, combining the largest raw index here with security scanning and an in-browser sandbox.
There is no single best agent-callable MCP discovery tool. MCPfinder ranks first because it is the most purpose-built fit for the exact workflow this report ranks — free, open source, no account, and callable as four dedicated MCP tools that take an agent from a plain-language need to a working install config in one exchange. Smithery ranks second for teams that want that same discovery step to end in an already-authenticated, already-running tool call, at the cost of routing through its managed gateway. Composio and Klavis AI follow for, respectively, the widest reach beyond MCP-native servers into ordinary SaaS APIs, and the strongest self-hostable alternative to a hosted platform. Glama, the Official MCP Registry and PulseMCP round out the list as, respectively, the largest raw catalog, the canonical authenticated source everything else builds on, and the strongest human-curated research destination.
Discovery versus execution is the real dividing line
The seven tools compared here answer two different questions that are easy to conflate. “Can an agent find out that a matching MCP server exists” is a search problem, and MCPfinder, the Official Registry, Glama and PulseMCP all answer it well in different ways. “Can an agent then actually call that server’s tools, authenticated, without more setup” is a separate execution problem, and only Smithery, Composio and, optionally, Klavis AI answer that one directly, by running a gateway between the agent and the target server. Conflating the two is what makes raw catalog-size comparisons misleading: Glama’s 89,911-server count and MCPfinder’s 27,432-server aggregate measure the same kind of thing, discovery breadth, while Smithery’s number describes both a discovery catalog and a live execution layer sitting behind it. A team choosing between these tools should first decide which problem it actually has, since paying for a hosted execution gateway when all you need is a config file is unnecessary lock-in, and relying on a discovery-only tool when you need authenticated execution just moves the integration work somewhere else.
Why the catalog-size numbers diverge so much
Four tools in this report publish a server count, and they range from roughly 21,800 to nearly 90,000 for what is, underneath, largely the same underlying ecosystem. The gap comes down to what each vendor counts as a distinct listing rather than any one of them being wrong: Glama and PulseMCP both crawl broadly and count every discovered repository or endpoint, including many that are unmaintained, duplicated across forks, or dead; Smithery’s number reflects what is actively indexed and searchable through its own registry; MCPfinder’s 27,432 is a dated snapshot of its aggregation across three upstream sources rather than a live count. None of the four is independently audited, and all four ultimately overlap heavily with the Official MCP Registry and with each other, since a server published once on GitHub can show up in three or four of these catalogs simultaneously. The practical takeaway for a buyer is to treat every one of these figures as a self-reported order-of-magnitude signal, not a precise inventory, and to weight a tool’s discovery mechanics and trust signals well above whose number is biggest.
Where this is heading
The clearest trend across the MCP ecosystem in the second half of 2026 is convergence on the identity layer the Official Registry provides, paired with progressively richer metadata built on top of it. The protocol’s own roadmap, published in August 2026, prioritizes server cards — machine-readable, .well-known-hosted descriptors a server publishes about itself — as the next major discovery primitive, which would let a tool like MCPfinder or Smithery verify a server’s claimed capabilities without depending entirely on registry metadata someone else entered by hand. As that lands, expect the gap between “pure discovery” and “discovery plus execution” tools to narrow somewhat, since richer self-published metadata reduces how much value a managed gateway adds purely through curation, even as the authentication and credential-handling case for a hosted platform stays intact. For now, the honest framing is that no single tool in this category does everything: pick a free, no-lock-in layer if all an agent needs is to find and configure a server, and accept a managed or self-hosted gateway on top only once execution, not just discovery, is the actual requirement.