Marginal AI works as a research layer for the AI assistants you already use. Connect Claude, ChatGPT, Perplexity, Gemini, Codex, Cursor or Meta AI, and when you ask about companies, events and news, reported financials, markets or the economy, your assistant asks Marginal AI, which answers exactly as it does in the app, with its sources.
It is available on every plan and draws on your Compute Units (CU): a question uses CU like the same question in the app, plus 1 CU per question from 10 December 2026 (none through ChatGPT or Codex). Developer tools such as Claude Code, Codex and Cursor can also make data calls (0.5 CU each; see Cost and limits).
Building your own software on Marginal AI data? See the Enterprise REST API on the developer page.
Server address: https://
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 and find Marginal AI in the directory.
- Click Connect, sign in to Marginal AI if asked, review the request, and approve it.
- If you prefer, choose Add custom connector instead, name it Marginal AI and paste
https://.api.marginal-ai.com/ mcp
ChatGPT
- Open Plugins, choose Add > Add custom MCP server.
- Name it Marginal AI and paste
https://.api.marginal-ai.com/ mcp - Tick I understand and choose Create as a plugin. ChatGPT asks you to sign in to Marginal AI and approve.
Perplexity
- Open Settings > Connectors and add a custom remote connector named Marginal AI, with OAuth sign-in and
https://.api.marginal-ai.com/ mcp - Perplexity then asks you to sign in to Marginal AI and approve access.
Gemini
- On gemini.google.com, open Settings > Connected apps and add a custom app with
https://.api.marginal-ai.com/ mcp - Gemini then asks you to sign in to Marginal AI and approve access.
- Google offers custom apps on personal Google accounts in the US, in English, for ages 18+.
Claude Code
claude mcp add --transport http marginal https://api.marginal-ai.com/mcpThen run / inside Claude Code, choose marginal and authenticate in the browser window that opens.
Codex
Add to ~/:
[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.
Meta AI
Muse Code: add this to the mcp_servers block of the Muse Code settings file:
{
"mcp_servers": {
"marginal": {
"transport": "streamable_http",
"url": "https://api.marginal-ai.com/mcp",
"mode": "optional"
}
}
}Then run muse mcp login marginal.
Muse (muse.ai and the Muse app, US and Canada): go to Settings > Connectors and add a custom connector with https://, or ask Muse to add it. Sign in to Marginal AI and approve. Custom connectors are added in Muse; the Meta AI app does not offer them yet.
Siri
In the Marginal AI iPhone app, say “Hey Siri, ask Marginal AI” and ask your question. Marginal AI answers it just as the app does: if the answer is ready within a few seconds, Siri reads you its opening and the full answer with sources is in the app; otherwise you get a notification when it is ready. Say "deep dive" for a Deep Dive.
To skip “Hey Siri”, go to Settings > Accessibility > Touch > Back Tap and set Double Tap to “Ask Marginal AI” (or use the Action button on iPhone 15 Pro and later).
You can also connect Marginal AI in the Claude app (Settings > Connectors, with its tools set to Always allow) and say “Hey Siri, ask Claude”.
Questions asked through Siri use CU like the same question in the app; from 10 December 2026 each answered question also carries 1 CU.
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>.
Tips
- How to ask. In ChatGPT, start your message with @Marginal AI, for example "@Marginal AI what happened at Nvidia this month?". In Claude, switch Marginal AI on for the chat in the tools menu and start with "Using Marginal AI, ...". Ask normally for a Brief answer; say "deep dive" for a Deep Dive, which takes longer and uses more CU.
- Using Marginal AI in the background (for example “Hey Siri, ask Claude” or scheduled tasks): set the Marginal AI tools to Always allow in your agent, because a background run cannot ask for your approval.
Use it without naming it
Add one standing instruction and your assistant asks Marginal AI on its own. The wording to add: "For questions about companies, markets and the economy, ask Marginal AI."
- Claude (web, desktop and phone): Settings > Profile, in the personal preferences box (or a Project’s instructions). Keep the Marginal AI connector switched on for your chats.
- Claude Code: add it to your
CLAUDE.md. The Marginal AI plugin for Claude Code already includes it. - Codex: add it to your
AGENTS.md. - ChatGPT: add it under Settings > Personalization > Custom instructions. ChatGPT still needs the plugin added to the chat with @Marginal AI.
- Perplexity and Gemini: add it to the assistant’s own personalisation or instructions settings.
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. |
ask_marginal_ai / research_result | Ask Marginal AI a question and get its cited answer, exactly as the app answers it. Brief by default; a Deep Dive when you ask for one. Uses CU like the same question in the app, plus 1 CU per question from 10 December 2026 (none through ChatGPT or Codex); checking on an answer still in progress is free. Claude, ChatGPT, Perplexity, Gemini and Meta AI get these two tools only (or, if you connect them for data only, the data tools instead); developer tools and API keys also get the data tools listed here. |
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 | |
|---|---|---|
Questions (ask_marginal_ai) | CU like the same question in the app, plus 1 CU per question from 10 December 2026 (none through ChatGPT or Codex) | |
| Event tools | 0.5 CU per call, including up to 10 events; each further event 0.02 CU (a 50-event page costs 1.3 CU) | |
| SEC and macro tools | 0.5 CU per call | |
| Distinct events per calendar month | 250 | Basic 2,500; Intermediate 4,000; Advanced 8,000; Business 10,000 plus 1,000 per extra seat, up to 30,000 |
| Tool calls per minute | 20 | 60 |
| Tool calls per day (safety ceiling) | 10,000 | 10,000 |
Questions asked with an Enterprise company key, or through ChatGPT or Codex, carry no per-question fee.
Re-reading the same events does not count again towards the monthly event limit, and a company’s keys and members share one count. Over the limit, event tools return a monthly_ error with the reset date; SEC and macro tools keep working. The Enterprise API has no monthly event limit.
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.
- You can untick research on the consent screen to connect an agent for data only.
- 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
