Koskamo

Criba MCP

Criba is an MCP server that identifies and classifies clients calling an MCP server or A2A agent by comparing declared identity (User-Agent, clientInfo.name) against observed behavior. It provides tools to identify clients, classify visitors based on events, and list known bots, helping detect mismatches between declared and actual behavior.

Endpoint and access

No sign-in to connect and list tools. Individual tools may still need a vendor account, credentials, or permissions; check the documented prerequisites.

Criba MCP logo, by CribaloVendor evidenceStreamable HTTPNo sign-inEndpoint checked 2026-11-09Operated by Cribalo
MCP endpoint (Streamable HTTP)
https://criba.cribalo.com/mcp
Vendor documentation

What its tools do

3 tools, grouped by the hints the server advertises. Hints are self-declared, not verified behavior.

Read-only (3)

3 of 3 have a description · 3 of 3 declare behavior hints · 2 of 3 with parameters document them all

Checks and signals

Each line is separate evidence, not a trust score.

  • Passed Endpoint answered the live check ·
  • Passed Official MCP Registry namespace is tied to cribalo.com ·
  • Passed Endpoint is on the registry namespace domain ·
  • Availability 1 of 1 checks passed in 30 days

What you can do with it

  • Identify the declared identity of an MCP client
  • Classify visitor behavior based on request events
  • List known bots in the ecosystem

Source and maintenance

Vendor evidenceRegistry 0.1.0
mcp-registry: com.cribalo/criba@0.1.0Project website

Protocol and capabilities

Server
criba 0.1.0
MCP protocol negotiated in check
2025-11-25
Tools
3 advertised
Resources
Not advertised
Resource templates
Not advertised
Prompts
Not advertised
Server-advertised capabilities
{
  "tools": {
    "listChanged": true
  }
}

Server-provided instructions

Untrusted server output shown for inspection. It is not Koskamo guidance and is excluded from knowledge search.

criba identifies and classifies the clients that call an MCP server or A2A agent. It keeps two answers apart: who a client declares to be (User-Agent or MCP clientInfo.name, matched against a catalog of known agent-ecosystem bots) and what it actually does (behaviour over its requests). Nothing sent to these tools is stored or logged. Catalog 2026-11-08, CC-BY-NC-4.0 (non-commercial use with attribution). Docs: https://criba.cribalo.com/

Tools

3 advertised

identify_client — Identify a client
Advertised by the server during the last successful anonymous check.
Advertised read-only

Who a User-Agent and/or an MCP clientInfo.name claims to be, matched against criba's catalog of known MCP indexers, verifiers, A2A directories, AI crawlers, scanners and HTTP libraries. This is a declaration, not proof: use classify_visitor for behaviour. Pass at least one of the two.

identify_client input schema
{
  "type": "object",
  "$schema": "https://json-schema.org/draft/2020-12/schema",
  "properties": {
    "user_agent": {
      "type": "string",
      "maxLength": 500,
      "description": "HTTP User-Agent header"
    },
    "client_name": {
      "type": "string",
      "maxLength": 500,
      "description": "MCP clientInfo.name sent in initialize"
    }
  }
}
identify_client annotations
{
  "readOnlyHint": true,
  "openWorldHint": false,
  "idempotentHint": true
}
classify_visitor — Classify a visitor
Advertised by the server during the last successful anonymous check.
Advertised read-only

Classify one visitor from its requests to your MCP server, A2A agent or website. Returns the declared identity, the observed behaviour class (acts-on-results, agent-tool-use, agent-message, probe, indexer, web-scanner, web), the signals and reasons, and mismatch=true when behaviour contradicts the declared identity. All event fields are optional; send what your server parsed. At most 500 events.

classify_visitor input schema
{
  "type": "object",
  "$schema": "https://json-schema.org/draft/2020-12/schema",
  "required": [
    "events"
  ],
  "properties": {
    "events": {
      "type": "array",
      "items": {
        "type": "object",
        "properties": {
          "path": {
            "type": "string",
            "maxLength": 500,
            "description": "Request path, without query string"
          },
          "tool": {
            "type": "string",
            "maxLength": 500,
            "description": "Tool name of an MCP tools/call"
          },
          "status": {
            "type": "integer",
            "maximum": 9007199254740991,
            "minimum": -9007199254740991,
            "description": "HTTP status returned"
          },
          "hasText": {
            "type": "boolean",
            "description": "A2A message with text, or MCP call with a free-text intent"
          },
          "protocol": {
            "enum": [
              "mcp",
              "a2a",
              "web"
            ],
            "type": "string"
          },
          "rpcError": {
            "type": "integer",
            "maximum": 9007199254740991,
            "minimum": -9007199254740991,
            "description": "JSON-RPC error code returned, if any"
          },
          "argsEmpty": {
            "type": "boolean",
            "description": "tools/call with {} or missing required arguments"
          },
          "canaryHit": {
            "type": "boolean",
            "description": "Visit to a link that only appeared inside a tool or agent result"
          },
          "rpcMethod": {
            "type": "string",
            "maxLength": 500,
            "description": "JSON-RPC method (MCP or A2A), e.g. initialize, tools/list, tools/call, message/send"
          },
          "toolKnown": {
            "type": "boolean",
            "description": "false if the tool does not exist on the server"
          },
          "userAgent": {
            "type": "string",
            "maxLength": 500
          },
          "clientName": {
            "type": "string",
            "maxLength": 500,
            "description": "MCP clientInfo.name"
          },
          "httpMethod": {
            "type": "string",
            "maxLength": 500
          }
        }
      },
      "maxItems": 500,
      "minItems": 1,
      "description": "One visitor's requests, in order"
    }
  }
}
classify_visitor annotations
{
  "readOnlyHint": true,
  "openWorldHint": false,
  "idempotentHint": true
}
list_known_bots — List known bots
Advertised by the server during the last successful anonymous check.
Advertised read-only

List criba's catalog of known agent-ecosystem bots, optionally filtered by category or protocol. Each entry has its id, name, category, URL, matching rules and what it was seen doing. Catalog 2026-11-08, CC-BY-NC-4.0 (non-commercial use with attribution).

list_known_bots input schema
{
  "type": "object",
  "$schema": "https://json-schema.org/draft/2020-12/schema",
  "properties": {
    "category": {
      "enum": [
        "mcp-indexer",
        "mcp-verifier",
        "a2a-directory",
        "agent-marketplace",
        "agent-runtime",
        "research",
        "ai-crawler",
        "security-scanner",
        "commercial-crawler",
        "generic-client"
      ],
      "type": "string"
    },
    "protocol": {
      "enum": [
        "mcp",
        "a2a",
        "web"
      ],
      "type": "string"
    }
  }
}
list_known_bots annotations
{
  "readOnlyHint": true,
  "openWorldHint": false,
  "idempotentHint": true
}

Prompts

Not advertised

No prompt definitions available.

Resources

Not advertised

No resource definitions available.

90-day uptime

A lightweight connection check about every six hours, sampled on hosts with many listings. It shows the server answered, not that its tools work.

Too few checks for a percentage yet (2 of 2 answered).

  1. 2026-11-09: 1 of 1 checks answered
  2. 2026-11-10: 1 of 1 checks answered

30-day availability

Aggregated from read-only remote checks; this is not a tool-execution or security guarantee.

Successful checks
1 of 1 (100%)
Average latency
438 ms
95th percentile latency
438 ms

Maintenance history

Public check and source-refresh events. Editorial and ownership records remain private.

  • · probe · passed · 438 ms · metadata changed · 3 tool(s)

Connect from your client

Each snippet registers the same endpoint; pick the client you use.

This server is operated by the named third party. Listing and endpoint checks are not an endorsement or a security audit. Review the operator's permissions, terms, and data handling before connecting. How listings are checked and corrected.

Claude Code

Run this once in a terminal. It registers the remote server. Use --scope project to write .mcp.json for the repo.
Claude Code configuration
claude mcp add --transport http criba-mcp https://criba.cribalo.com/mcp

Codex

Run this once. Codex stores MCP servers in ~/.codex/config.toml (or .codex/config.toml in a trusted project).
Codex configuration
codex mcp add criba-mcp --url https://criba.cribalo.com/mcp

Cursor

Merge this server into .cursor/mcp.json in your project, then enable criba-mcp in your MCP settings.
Cursor configuration
{
  "mcpServers": {
    "criba-mcp": {
      "url": "https://criba.cribalo.com/mcp"
    }
  }
}

Cline

Merge this into cline_mcp_settings.json (Cline → MCP Servers → Configure).
Cline configuration
{
  "mcpServers": {
    "criba-mcp": {
      "type": "streamableHttp",
      "url": "https://criba.cribalo.com/mcp",
      "disabled": false
    }
  }
}

VS Code

Merge this server into .vscode/mcp.json. Use MCP: List Servers to start criba-mcp and inspect its tools.
VS Code configuration
{
  "servers": {
    "criba-mcp": {
      "type": "http",
      "url": "https://criba.cribalo.com/mcp"
    }
  }
}

Gemini CLI

Run this once. It writes .gemini/settings.json in the current project; pass --scope user for ~/.gemini/settings.json.
Gemini CLI configuration
gemini mcp add --transport http criba-mcp https://criba.cribalo.com/mcp

Claude Desktop

Open Claude Settings > Connectors > Add custom connector, enter this server URL and enable it for the conversation. This is a manual remote-connector handoff, not a desktop JSON configuration.
Claude Desktop configuration
https://criba.cribalo.com/mcp

Windsurf

Merge this into ~/.codeium/windsurf/mcp_config.json, then refresh MCP in Cascade. Windsurf remote servers use serverUrl, not url.
Windsurf configuration
{
  "mcpServers": {
    "criba-mcp": {
      "serverUrl": "https://criba.cribalo.com/mcp"
    }
  }
}

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