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Apidefects MCP server

Which MCP servers are Apidefects's own, from the official registry and from asking its own domain, whether they answer, and what they offer. A program checked each of these, nobody copied them from a product page.

read 2026-10-21

← Back to Apidefects

Whose server it is
  • Registry namecom.apidefects/errataverified in the MCP registry

The registry name sits under apidefects.com. The registry only lets a publisher use that namespace after proving control of the domain through DNS or HTTP.

When we asked itchecked 2026-10-21
  • Stateanswerschecked 2026-10-21
  • Tools1
  • Server calls itselferrata
  • Server versionerrata-2026-09-10@dcb7ccbec3ce
  • Protocol version2025-06-18

On 2026-10-21 the server answered initialize and tools/list without a sign-in. First answer in 46 ms.

Should an agent connect itNot proven either way yet
  • Whether its tools do the product's job has not been judged yet.
  • Checked on 6 of the 7 days it takes to judge reliability.

Said by rules from the measurements above. The likely first call is a model's pick from the tool list; read its description before relying on it.

Measured dailydaily checks: 6, the first on 2026-10-21
  • INITE MCP scoreafter a weeka score needs 7 daily checks: 6 so far
  • Answeredmeasuring6 of the 7 daily checks it takes to print a share
  • Median first answer120 ms
  • Space in an agent's context≈ 315 tokensthe definitions of all its tools (1), which an agent carries on every turn
  • Tool definitionsB · 83 of 100
  • Typed results0 of 1 toolsdeclared outputSchema: results come typed, read once
  • Not saying whether it only reads or can destroy: 1 of 1

What an agent can do with it

  • not sure · check an MCP server or API before installing it
  • not sure · find MCP servers whose packages cannot be installed
  • not sure · find API specifications pointing at hosts that no longer exist

Each of the product's use cases, put to Jev against this server's tool list: can an agent do it with these tools?

Worth a look

None of the five warning signs in these definitions.

A program checks the server once a day: initialize and tools/list, no model. Tokens are the definitions' length at about four characters a token. The grade averages six checks of every tool's name, description, schema and annotations; it says how well the tools are described, not whether they work. The score weighs what was measured and nothing else: answering (25%), doing the product's job (25%), definitions (20%), context (10%), use (10%) and how readily a client connects (10%). A part that was not measured is left out, and a hidden instruction caps the score at 40. The state of vendors' MCP servers: method and numbers →

Tools it offers1 tools · read 2026-10-21
  • check_defects

    Before using an MCP server or an API operation, ask what is known to be wrong with it. Takes one identity: an MCP registry entry (io.github.owner/repo), a deployment URL, an OpenAPI document URL, or a host. Answers one of three things…

How to connect

Add the server to your MCP client config. Claude Desktop, Cursor and most other clients read this shape:

{
  "mcpServers": {
    "errata": {
      "type": "http",
      "url": "https://apidefects.com/mcp"
    }
  }
}

Add it

Claude Code, in a terminal

claude mcp add --transport http apidefects https://apidefects.com/mcp

Add to CursorAdd to VS Code

claude.ai, ChatGPT and other clients: add https://apidefects.com/mcp as a custom connector in the settings.

Each line is something a program found when it went looking: the registry entry, the server's own answer, a spec that parses. A missing line means we did not find it, not that it does not exist.