Standards signals
How MCP servers and Agent Skills line up with the open standards
Plain signals, not pass/fail, observed from public registry data and a read-only, unauthenticated check. MCP (spec revision 2026-07-28) and Agent Skills are now projects of the Agentic AI Foundation (AAIF). Neither AAIF nor the MCP project certifies servers, and nothing here changes a Copilot Studio verdict.
Own a server? modelcontextprotocol/conformance: test your own server. Own a skill? skills-ref validate.
MCP servers
Counts are over 47,350 directory entries after dedupe, before bulk publishers are grouped, so they differ from the unique counts on the home page (how the numbers add up). Endpoint checks last ran 2026-10-23.
| Signal | Entries | Share | Spec |
|---|---|---|---|
| Listed in the official MCP Registry | 47,269 | 99.8% | MCP Registry |
| server.json schema 2025-12-11 (current) | 44,161 | 93.4% of registry | server.json schema changelog |
| Remote Streamable HTTP | 30,183 | 63.7% | Transports: Streamable HTTP |
| HTTP+SSE only | 728 | 1.5% | Transports: backward compatibility (HTTP+SSE) |
| Local package only (stdio or self-hosted HTTP) | 15,864 | 33.5% | Transports: stdio |
| Answered an MCP initialize without credentials | 19,239 | 64.3% of 29,903 checked | Lifecycle: initialization |
| Need sign-in | 7,885 | 26.4% of checked | Authorization: RFC 9728 metadata |
| …and publish RFC 9728 metadata | 6,755 | 85.7% of sign-in | Authorization: RFC 9728 metadata |
| …and the authorization server advertises CIMD | 2,202 | 32.7% of 6,724 with metadata | Client registration: CIMD |
| …and advertises the RFC 9207 issuer parameter | 2,475 | 36.8% of 6,724 with metadata | Authorization: RFC 9207 iss |
| server/discover lists 2026-07-28 | 369 | 1.8% of 20,884 checked | server/discover |
Spec version spoken
The protocol version in the initialize answer, over 19,179 endpoints that answered without credentials. We offer 2025-06-18 and, when a server accepts that, offer 2025-11-25 once more. A server can answer with any version it supports. Versioning
| Version | Endpoints | Share |
|---|---|---|
2026-07-28 | 127 | 0.7% |
2025-11-25 | 10,857 | 56.6% |
2025-11-05 | 4 | 0.0% |
2025-06-18 | 2,533 | 13.2% |
2025-03-26 | 4,684 | 24.4% |
2024-11-05 | 643 | 3.4% |
unknown | 331 | 1.7% |
server.json schema versions
| Schema | Entries |
|---|---|
2025-12-11 (current) | 44,161 |
2025-10-17 | 650 |
2025-09-29 | 1,720 |
2025-09-16 | 155 |
2025-07-09 | 581 |
Agent Skills
| Signal | Skills | Share | Spec |
|---|---|---|---|
| Meet the agentskills.io required fields | 2,172 | 96.2% | Spec: frontmatter |
| …and the name matches the folder | 2,151 | 95.3% | Spec: name |
Use the experimental allowed-tools field | 202 | 8.9% | Spec: allowed-tools |
Of 2,257 skills from the repos we index. See Skills.
Maintenance signals
An estimate from public metadata, not a judgment of the project. Each line on a server page is dated and links to its source. The directory's “Hide servers with deprecation signals” box hides entries with any of the first five.
| Signal | Entries | Source |
|---|---|---|
| Official MCP Registry status deprecated or deleted (not listed in the directory) | 618 (618 deprecated) | MCP Registry |
| npm: latest version marked deprecated | 353 | registry.npmjs.org, checked 2026-10-23 |
| PyPI: latest release yanked | 9 | pypi.org JSON API, checked 2026-10-23 |
| PyPI: “Development Status :: 7 - Inactive” | 12 | pypi.org JSON API |
| GitHub repo archived | 272 | GitHub |
| Endpoint unreachable 5 checks in a row | 0 | Our check history (up to 4 checks so far) |
| Directory entries with any of the signals above (deduplicated) | 608 | |
| No commits in 12+ months (shown, never a verdict) | 171 | GitHub last push, 27,935 repos with data |
GitHub archived flags are included. The unreachable signal needs 5 checks with no answer at all (DNS, refused or TLS failures); rate limits (HTTP 429), 5xx errors and timeouts count as unknown, never as down, and keep the last good result. Endpoints are checked about once a week.
Data built 2026-10-24. Corrections: hello@mcp4copilot.dev.