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Independent measurements of remote MCP servers. Every observation has a timestamp.

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MCP server · Code & DevOps

criba: who is calling your MCP server

By cribalo.com

Identify who calls your MCP server or A2A agent: declared identity vs observed behaviour.

WebsiteAI models & agentsSecurity & identity
Connect to criba: who is calling your MCP server
Checks passed
11 / 22

3 failed · 8 not measured

Median response
54 ms

Median of successful probes over 7 days

30-day uptime
Not measured

Share of countable probes over 30 days, including daily rollups. Auth challenges are excluded.

Discovered tools
3

Tool definitions returned by this server

Independent monitoring

Health & checks

Status history

Outdated check

Last connection measurement is over 24 hours old. Current availability is unknown.

Last checked
Check summary by test group
Test areaPassedFailedUnmeasured
ConnectionCan a client connect and discover tools?
500
Reliability & speedDoes it respond consistently and quickly?
004
Access & authenticationWhat is required to use this server?
102
Tool qualityAre the tool definitions usable by an agent?
310
Publisher identityCan the publisher be traced to its source?
222

Unmeasured means there is not enough evidence to decide. How these checks work

Inspect individual checks 22 recorded

Core

  • Pass
    Reachable

    Latest probe returned HTTP 200 in 54 ms.

  • Pass
    Valid handshake

    protocolVersion 2025-11-25, serverInfo.name criba.

  • Pass
    Lists tools

    tools/list returned 3 tools.

  • Pass
    Current protocol

    Negotiated 2025-11-25. The bar is 2025-06-18 or newer.

  • Pass
    HTTPS

    The endpoint URL is https.

Performance

  • Not measured
    Fast (p50)

    Median latency 54 ms over 1 samples in 7 days. The bar is 1000 ms. Need at least 5 samples.

  • Not measured
    Consistent (p95)

    95th percentile 54 ms over 1 samples in 7 days. The bar is 3000 ms. Need at least 20 samples.

  • Not measured
    Reliable (uptime)

    1 of 1 attempts returned a tool list in 30 days (100%). The bar is 99%. Need at least 30 samples.

  • Not measured
    Stable tool list

    Fewer than two successful probes in 30 days, so tool-list stability is not measured.

Access

  • Pass
    Open access

    tools/list succeeded with no credential, and the record declares none.

  • Not measured
    Standard auth

    Auth is not required, so the OAuth metadata check does not apply.

  • Not measured
    Free tier cited

    No publisher quote has been checked.

Tools

  • Pass
    Tools described

    Every tool description is at least 20 characters.

  • Pass
    Valid input schemas

    Every inputSchema is a JSON Schema object.

  • Fail
    Parameters documented

    3 of 5 parameters have a description (60%). The bar is 80%.

  • Pass
    Safety hints

    Every tool sets readOnlyHint or destructiveHint.

Publisher

  • Pass
    Verified namespace

    Listed in the Official MCP Registry.

  • Fail
    Website matches publisher

    The website host does not match the reverse-domain namespace.

  • Fail
    Source repo linked

    No repository URL is on file.

  • Not measured
    Repo owner matches

    This namespace is not an io.github login, so the owner comparison does not apply.

  • Pass
    Recently updated

    Updated 2026-11-09T09:06:46.245914Z, within 180 days.

  • Not measured
    Open-source licence

    No GitHub repository to ask about a licence.

Start using criba: who is calling your MCP server

Connect to this server

Choose your client, copy the configuration, then enable the server in your client’s MCP settings.

Run this command in your terminal, then restart Claude Code.

Claude Code

claude mcp add --transport http criba-who-is-calling-your-mcp-server https://criba.cribalo.com/mcp

Capabilities

Tools 3

classify_visitor

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.

Discovered
identify_client

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.

Discovered
list_known_bots

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).

Discovered

Recent measurements

Probe history

View status
Latest stored probes. Raw probe rows are kept for 14 days.
CheckedResultResponseTools
Connected54 ms3

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