Six months after the Model Context Protocol went from niche developer experiment to infrastructure primitive, the ecosystem has a shape. Not a finished one — servers are still shipping weekly, categories are still forming, and payment-gated APIs are just starting to appear. But enough has accumulated that you can take a real measurement. This is what the MCP ecosystem looks like in May 2026.

By the Numbers

The AgentNDX directory tracks 350 curated MCP servers — hand-reviewed, quality-scored, and organized by category. These are not scraped from package indexes. Every server in the directory has been evaluated for documentation quality, install reliability, and real-world usability.

Of those 350:

  • 163 are verified — meaning they have confirmed working installs, documented auth, and at least two real use cases
  • 303 include a working install command — copy-paste ready for Claude Desktop, Cursor, or any MCP-compatible client
  • 3 support x402 payment-gated access — the first wave of pay-per-call AI services is here, but small
  • 350 total across 10 categories — the ecosystem is broader than most developers realize

The raw ecosystem is larger. Aggregating across public registries, GitHub, and third-party indexes puts the total server count above 48,000. Most of that long tail is unmaintained, undocumented, or duplicative. The 350 in the curated directory represent what is actually usable today.

What’s Growing: Data and Infrastructure Lead

The two biggest categories by server count are data (77 servers) and infrastructure (54 servers). That is not surprising — these are the use cases where MCP solves a real problem that REST APIs handle poorly.

Data servers cover database connections, ETL pipelines, vector search, analytics, and enrichment. When an AI agent needs to query a database, run a search, or pull structured records, MCP gives it a standardized interface. The category grew faster than any other in Q1 2026, driven largely by database tooling (Postgres, SQLite, Supabase, PlanetScale) and enrichment providers (Clearbit, Apollo, Hunter).

Infrastructure servers cover cloud platforms, deployment pipelines, monitoring, and CI/CD. These are the servers that let agents operate on infrastructure — not just read it. The category includes AWS, GCP, and Azure integrations alongside dedicated DevOps tooling from Vercel, Railway, Cloudflare, and Render.

Productivity (56 servers) rounds out the top three. Calendar integrations, document processors, email clients, and project management tools are all here — the connective tissue between AI agents and the software knowledge workers already use.

What’s Emerging: Payments, Identity, and AI-to-AI

Three categories are smaller but growing faster than their current counts suggest.

Payments (21 servers) is the most structurally interesting. The x402 protocol gives AI agents a native way to pay for services without human intervention — HTTP 402 with a payment header, settled on-chain. Only 3 servers in the directory support x402 today. That number will be materially different by Q3 2026 as payment-gated AI services become a real business model.

Identity (14 servers) covers auth, SSO, and access control. As agents start taking actions on behalf of users — booking meetings, sending emails, submitting forms — identity becomes critical infrastructure. The category is small because the hard problems (delegated auth, scoped permissions, session management for agents) are still being solved.

AI (35 servers) is agent-to-agent tooling: model gateways, embedding providers, retrieval systems, and orchestration layers. This category exists because AI agents increasingly need to call other AI services as part of their workflows. It is the infrastructure for the agentic web’s middle layer.

What the Numbers Don’t Show

The curated count (350) versus the raw count (48K+) tells you something about the maturity problem. MCP lowered the barrier to publishing a server to nearly zero. That is good for experimentation. It is bad for discoverability.

The real constraint for builders right now is not finding MCP servers — it is finding ones that work reliably. Verified rate across the curated directory is 46% (163/350). In the broader ecosystem, the usable fraction is much lower. Servers without install commands, servers whose auth model is undocumented, servers whose last commit was five months ago — these are the norm in the long tail.

The category that has the highest verified rate is payments, where all listed servers are functional almost by definition (you can test them with a real transaction). The lowest verified rate is in the AI and web categories, where API surface areas change frequently and documentation lags behind.

What This Means for Builders

If you are building with MCP today, the practical takeaway is straightforward:

Start with the top 10 in your category. The directory’s quality score (0-5) surfaces the servers with the best combination of documentation, install reliability, and use case coverage. A score of 4+ is a strong signal that the server will work in a real workflow.

Treat x402-enabled servers as early infrastructure. The payment-gated model is not mature yet, but the pattern is clear. Services that today require API key billing will shift to per-call x402 settlement as agents become the primary consumer. Building familiarity with the protocol now is low-cost and high-return.

Watch the identity category. Every capability an agent gains — calendar access, email, CRM writes, infrastructure changes — creates an auth surface that needs to be managed. The identity servers shipping in 2026 will be foundational for what agents can do safely in 2027.

The MCP ecosystem in May 2026 is real, functional, and growing. It is not finished. But 350 curated servers across 10 categories, 163 of them verified, is enough to build serious agent workflows today.

FAQ

Q: How is the AgentNDX directory different from other MCP indexes? A: Most indexes aggregate from package registries without curation. AgentNDX reviews every server for documentation quality, working installs, and real use cases. The result is a smaller but more reliable directory — 350 curated versus 48K+ raw. Browse the directory to see the full list.

Q: What does “verified” mean for an MCP server? A: A verified server has a confirmed working install command, documented auth requirements, and at least two documented use cases. Verification does not mean the server is officially endorsed by its provider — it means we confirmed it works.

Q: How often is the directory updated? A: New servers are added weekly. The quality score and verified status are reviewed on a rolling basis. The Recently Added view shows servers added in the last 30 days.

Q: What is x402 and why does it matter for MCP? A: x402 is an HTTP payment protocol that lets AI agents pay for services autonomously — no human in the loop, no API billing account required. For MCP specifically, it enables pay-per-call server access. Learn more about x402 and MCP servers.