Castle MCP by usefulapi

Install

Pick the AI app you use, then copy the settings.

Passed 4/4 checks · What you ask goes through the maker’s server (castle.usefulapi.io) · ✓ Commands checked Nov 13, 2026

claude mcp add --transport http --scope user castle https://castle.usefulapi.io/mcp

{
  "mcpServers": {
    "castle": {
      "url": "https://castle.usefulapi.io/mcp"
    }
  }
}

{
  "servers": {
    "castle": {
      "type": "http",
      "url": "https://castle.usefulapi.io/mcp"
    }
  }
}

Which apps can use it

Based on how this server connects and on each app’s own docs, checked Nov 10, 2026.

Connect over the internet in

ClaudeChatGPTGooseLM StudioMsty StudioCherry StudioCursorVS Code + GitHub CopilotVisual StudioWindsurf (Devin Desktop)ZedKiroClineContinueJetBrains AI AssistantClaude CodeCodex CLIGemini CLIOpenCodenodecodeWarpLibreChatOpen WebUIRaycast

All apps, with pros and cons →

What it can do

Tool names and descriptions exactly as the server reported them on Nov 14, 2026. The maker wrote them, not us; we show them as plain text.

• castle_get_events_schema

  List the event fields you can filter and group on, with their types. Read this first — the other query tools need real field names. Castle: GET /v1/events/schema.

• castle_search_events

  Query the security event stream — logins, registrations, transactions and their risk verdicts. Read-only despite being a POST: Castle takes the query in the body. Castle: POST /v1/events/query.

• castle_group_events

  Aggregate matching events by one or more fields — the fast way to see which IPs, devices or countries dominate a spike. Read-only despite being a POST. Castle: POST /v1/events/group.

• castle_search_lists

  Find the allow/deny lists defined in the environment. Read-only despite being a POST. Castle: POST /v1/lists/query.

• castle_get_list

  Fetch a single list with its primary and secondary field definitions. Castle: GET /v1/lists/{id}.

• castle_search_list_items

  Search the entries of one list — the blocked IPs, emails or device ids it holds. Read-only despite being a POST. Castle: POST /v1/lists/{list_id}/items/query.

• castle_count_list_items

  Count the entries in one list, with the same optional filters as the search. Read-only despite being a POST. Castle: POST /v1/lists/{list_id}/items/count.

• castle_get_list_item

  Fetch a single list entry — its value, who added it, the comment and its archive time. Castle: GET /v1/lists/{list_id}/items/{id}.

• castle_create_list

  Create a new allow or deny list. primary_field is the event field its entries match on, e.g. ip or user.email. Castle: POST /v1/lists.

• castle_update_list

  Rename a list or change its colour or description. Castle: PUT /v1/lists/{id}.

• castle_create_list_item

  Add an entry to a list — for example block an IP or an email. This changes live policy behaviour. Castle: POST /v1/lists/{list_id}/items.

• castle_update_list_item

  Change the comment on a list entry. Castle: PUT /v1/lists/{list_id}/items/{id}.

• castle_archive_list_item

  Archive a list entry so it stops matching. Reversible with castle_unarchive_list_item. Castle: DELETE /v1/lists/{list_id}/items/{id}/archive.

• castle_unarchive_list_item

  Restore a previously archived list entry so it matches again. Castle: PUT /v1/lists/{list_id}/items/{id}/unarchive.

Basic checksi

We check information anyone can see; we have not read the code. Checks that do not apply are left out of the count. · Checked Nov 16, 2026

• ✓ Pass

  Maker matches the repo

  The registry name was verified against the domain usefulapi.io (the registry checks domain ownership)

• ✓ Pass

  Still maintained

  Code last changed 2 days ago

• – Not applicable

  Has a licence

  Not applicable: a cloud server run by the owner of usefulapi.io; you don't run code from the repo

• ✓ Pass

  Endpoint responds

  Responded in 9 ms (HTTP 200)

• – Not applicable

  Sign-in with OAuth

  No sign-in needed

• ✓ Pass

  No hidden instructions in tool descriptions

  Read 14 tool descriptions and found no hidden instructions to the AI

What we check → · JSON

User reviews

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Compared with others in Cybersecurityi

• More stars than 0% of the other 1071 servers in this category
• Published to the registry more recently than 96% of the other 1071 servers in this category
• Basic checks equal to or better than 100% of the other 1071 servers in this category

Compared with every active server in this category in the registry. Stars count only when the publisher owns the repo.

Similar alternatives

Same category, other makers, commands already checked. Official ones first, then by stars.

Reading a card:↓ Downloads per weeki★ GitHub starsiThree pillars: reviews · checks · usageiUpdated = latest version published to the registryi

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README from the maker

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