Marginal AI works as a research layer for the AI agents you already use. Connect Claude, Codex, ChatGPT or Cursor, and your agent can look up corporate and market events, figures companies reported to the SEC, and macroeconomic data, with the source links to cite.
It is available on every plan and draws on your Compute Units (CU): each data call uses 0.5 CU, the lookups are free, and research questions use CU like a chat question.
Server address: https://api.marginal-ai.com/mcp
Before you start: you need a Marginal AI account. On your first connection you will be asked to approve the app and to accept the Agent API Terms.
Claude (web, desktop and mobile)
- Open Settings > Connectors > Add custom connector.
- Name it Marginal AI and paste
https://api.marginal-ai.com/mcp. - Click Connect, sign in to Marginal AI if asked, review the request, and approve it.
Claude Code
claude mcp add --transport http marginal https://api.marginal-ai.com/mcpThen run /mcp inside Claude Code, choose marginal and authenticate in the browser window that opens.
Codex
Add to ~/.codex/config.toml:
[mcp_servers.marginal]
url = "https://api.marginal-ai.com/mcp"
bearer_token_env_var = "MARGINAL_API_KEY"Create an API key in Marginal AI under Settings > Agent Access, and set it as the MARGINAL_API_KEY environment variable. Alternatively, leave out the bearer_token_env_var line and run codex mcp login marginal to sign in with your browser.
Other MCP clients
Any client that supports remote MCP servers over Streamable HTTP can connect. It can sign in with OAuth or send an API key as Authorization: Bearer <key>.
Tools
| Tool | What it returns |
|---|---|
resolve_company | Confirms a ticker or SEC CIK and returns the company’s identifiers. |
search_events | Events for a company, or across companies for one category or event type (up to 31 days), with source links and first-seen timestamps. known_as_of shows only what was knowable at a past moment, for backtests without lookahead. |
get_company_events | A company’s events by date or by materiality. |
get_event | One event in full, with its corroborating sources and the price reaction around it. |
get_new_events | Events first seen since a time you give (up to 7 days back), for polling. |
list_event_taxonomy | The event categories and types the event tools accept. |
list_industries | The industry groups covered (as in the app’s Industries filter) with company counts, or the companies in one group. |
get_sec_fact | One reported figure (for example revenue for a fiscal year), exactly as filed, with the filing link. |
get_sec_fact_series | A reported figure across periods, each point linked to its filing. |
list_macro_series | The available macroeconomic series. |
get_macro_series | Observations of one macroeconomic series. |
research_submit / research_result | Ask the Marginal AI analysis engine a research question and collect the cited answer. depth: brief (default) or deep for a Deep Dive. Uses CU like a chat question of the same depth. |
The data tools are read-only. They return factual data, not investment advice, and cannot place orders. resolve_company, list_event_taxonomy, list_industries and list_macro_series are free lookups (they tell your agent what it can ask for); every other data tool uses 0.5 CU per successful call.
Cost and limits
| Free plan | Paid plans | |
|---|---|---|
| Cost per data call | 0.5 CU | 0.5 CU |
| Tool calls per minute | 20 | 60 |
| Tool calls per day (safety ceiling) | 10,000 | 10,000 |
Your CU balance is what limits how much you can use. Daily counts reset at 00:00 UTC. Settings > Agent Access shows today’s calls and CU used. For bulk data or higher limits, contact us about the enterprise API.
Security and control
- You approve every app on a Marginal AI consent screen. Sign-in uses OAuth 2.1 with PKCE.
- An API key is shown once. Only a one-way hash of it is stored.
- Settings > Agent Access shows your connected apps and keys. You can disconnect or revoke any of them at any time. “Log out on all devices” also ends every agent connection.
Important
Marginal AI supplies intelligence, data and research, not investment advice or trade execution. It does not connect to brokerages or place, route or execute orders. You decide how to use its information, including through independent agents, and remain responsible for those agents’ actions and your own legal obligations. Data access, charges and licence restrictions are governed by the Agent API Terms. Our own contractual obligations and non-excludable liabilities remain unaffected.
Questions: support@marginal-ai.com
