Castling MCP

Use Castling in any AI with MCP

Connect once with the MCP URL, sign in with your Castling account, and ask any MCP-capable assistant for filing-backed EDGAR fundamentals. Pull KPIs and full statements, inspect reported segment composition, screen or compare companies, look up an issuer, browse annual filing metadata and material Form 8-Ks, search company summaries for context, and reach further back in history on paid plans when the data is available. Setup guides below cover popular clients; any AI with an MCP connector works the same way.

MCP server URL

https://mcp.castlingfinancial.com/mcp
Connect in ClaudeConnect in ChatGPT

Choose your assistant

Each setup takes a minute. OAuth uses your Castling suite account.

Claude

Add Castling as a custom MCP connector, authenticate once, then ask filing-backed questions in chat.

  1. Open Claude (Web).
  2. Go to Customize → Connectors → Add custom connector.
  3. Name it “Castling Financial” and paste the MCP URL below.
  4. Click Connect, sign in to Castling, and approve access.
  5. Start a chat and ask a fundamentals question.
Open Claude connectors

ChatGPT

Add Castling as a custom MCP connector, authenticate once, then ask filing-backed questions in chat.

  1. Open ChatGPT (Web).
  2. Go to Settings → Connectors (or your workspace’s custom connector flow).
  3. Name it “Castling Financial” and paste the MCP URL below.
  4. Connect, sign in to Castling, and approve access.
  5. Start a chat and enable the Castling connector.
Open ChatGPT connectors

Tools you get

Five read-only tools, the same surface Castle AI uses, over Castling's SEC fundamentals warehouse.

  • companyLook up a company by ticker or name, check which data snapshot you are reading, or explain coverage gaps.
  • fundamentalsPull filing-backed KPIs, XBRL line items, full statements, segment axes/series/composition, universe screens, and multi-company compares.
  • filingsAnnual Form 10-K, 20-F, and 40-F metadata, plus material Form 8-K and 8-K/A lists and document text.
  • searchSearch company summaries and data-quality notes for context. Not a source of KPI numbers.
  • scriptOne-call playbooks: company_kpis, compare, screen, and latest_8k (resolve + data pull bundled). Counts as one tool call.

Account and suite tiers

MCP needs a Castling account and a one-time OAuth sign-in. History depth and monthly call caps follow your suite tier.

Free

MCP: recent four fiscal years

50 MCP calls / month

Standard

MCP: history back to 2009 when available

500 MCP calls / month

Pro

MCP: history back to 2009 when available

2,000 MCP calls / month

Ultra

MCP: history back to 2009 when available

10,000 MCP calls / month

Paid history goes back to 2009 when available. Not every company has filings that far.

Sign in during the connector OAuth flow. Consent is handled at castlingfinancial.com/oauth/consent.

Try asking

After connecting, prompts like these exercise real Castling tools.

  • “What was Apple's revenue, net income, and free cash flow in 2023?”

  • “Make a line graph of Microsoft revenue and operating cash flow over the last four years.”

  • “Show Microsoft business segment revenue composition for the latest fiscal year.”

  • “Make a graph comparing Microsoft and Google net income for 2022 to 2024.”

  • “Screen for the top 25 USD companies by free cash flow in the latest annual year.”

  • “List NVIDIA recent Form 8-K filings and explain the latest documents.”

FAQ

Do I need to write code?
No. Any AI with an MCP connector can use Castling. Exact menus vary by client, plan, and workspace settings — Claude and ChatGPT are common examples with steps above.
What is the MCP URL?
https://mcp.castlingfinancial.com/mcp
Do I need a Castling account?
Yes. The MCP server is OAuth-protected. Sign in with your Castling suite account (Free, Standard, Pro, or Ultra) when the client starts authorization.
Does Castling give investment advice?
No. Castling retrieves and structures public company filing data. It does not provide brokerage, custody, or personalized investment recommendations. See the disclaimer.
Can I use other MCP clients?
Any client that supports remote MCP over HTTP with OAuth should work with the same URL, subject to that client's auth and transport support.

Ready to research inside your assistant?

Connect Castling once, then ask for filing-backed fundamentals without pasting statements into chat.

Connect to ClaudeConnect to ChatGPT