Brazilian stock (B3) data inside Claude, ChatGPT and Cursor

Dados B3 is an MCP server that gives your AI agent access to the fundamentals of 457 companies on the Brazilian stock exchange — banks and insurers included. Ask "what's Itaú's ROE?" or "is WEG's P/E expensive?" and the AI pulls the numbers on the spot, each traceable to its source account.

Connect (nothing to install)

Recording of the connector in ChatGPT: /demo/chatgpt. In Claude Code, one command: /claude-code.

Two URLs. For Claude and other MCP clients, with 36 tools:

https://dadosb3.com/mcp/

For ChatGPT, with 28 tools, open data only:

https://dadosb3.com/mcp/chatgpt/

In Claude Code, the plugin sets up the connection and adds the skill:

/plugin install dados-b3 --marketplace Val7h/dados-b3-mcp

Plugin code and instructions: github.com/Val7h/dados-b3-mcp.

Claude (app or web): Settings → Connectors → Add custom connector → paste the first URL (/mcp/).
ChatGPT: Settings → Apps/Connectors → developer mode → New connector → paste the second URL (/mcp/chatgpt/), authentication none. Its 28 tools need no key.
Cursor, VS Code and 100+ MCP clients: add it as a remote MCP server (Streamable HTTP).
An AI that can only open URLs (no connector, no headers): append ?chave=YOUR_KEY to any read route, e.g. https://dadosb3.com/empresas/PETR4/precos?chave=YOUR_KEY. A key in the URL stays in the history and in the logs of whoever uses it: prefer the free key for this.
Ask in plain language. WEGE3 and the methodology are open to try without a key.

What the AI can now look up

Tool	Answers
indicadores_anuais	ROE, ROIC, margins, growth, net debt/EBITDA (16 years)
multiplos	P/E, P/B, EV/EBITDA point-in-time (no look-ahead), trailing P/E
dividendos	payouts, yearly summary and dividend yield
scores	Piotroski F-Score (0-9, each criterion exposed) and Graham screen
reapresentacoes	restated financials — old vs. new figures side by side
fatos_contabeis	standardized line items with their source CVM account
trimestres	Q1/Q2/Q3 of the current year: interim-filing accounts, the quarter's price, margins and trailing ROE (the filing has no standalone Q4, and we do not derive one)
precos	the daily series (open, high, low, close, volume) in one call, with the events of the period; price not adjusted
eventos	splits, reverse splits, bonus issues and spin-offs, with the source and the net effect of the day
hoje	what changed in the last 30 days — filings published and re-sent, dividends, corporate actions
fii · fiis_ranking · screener_fiis	real-estate funds: point-in-time P/B, yield, vacancy, range filters
auditar_amostra	draws a sample and tells you to check it at the regulator, not against us
screener · metodologia · saude	filter by indicators, public formulas, database coverage

The table shows the main ones. The 36 tools of /mcp/: acessos_telecom, auditar_amostra, bancos, bdr, desempenho, dicionario, dividendos, etf, etfs_ranking, eventos, fatos_contabeis, fatos_relevantes, fii, fiis_ranking, fundos_da_acao, fundos_investimento, hoje, indicadores_anuais, indice, listar_empresas, listas, metodologia, multiplos, precos, producao_petroleo_gas, quanto_rendeu, reapresentacoes, saiu_da_bolsa, saude, scores, screener, screener_fiis, tarifas_energia, tesouro_direto, trimestres, veredito. Each one carries its name, description and arguments in the protocol's tools/list. Short list in /llms.txt.

Why this connector and not another

100% public methodology. Every number's formula and source account are published before the number — the AI can cite the source.

Nothing published without passing the tests. An invariant suite (the balance sheet balances, the income statement ties out, the price never precedes publication) runs before each update.

Multiples with no look-ahead bias. P/E uses the price of the first session from the day the filing was actually published — backtest-safe.

Banks and insurers done properly, with the financial chart of accounts (ROE, not ROIC).

Pricing

Free: 200 requests per day, no card. Pro: US$ 9.90/month, 10,000/day. The key goes in the tool's chave_api argument or the DADOS_B3_API_KEY variable.

Create a key / subscribe Honest comparison with competitors

Numbers on this page are live. Data version 2026-11-09-ancora-do-fre · page generated 2026-11-10 02:06 UTC. If this does not match /saude, you are reading a cached copy.

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Sources: CVM (open data, ODbL) and B3 (COTAHIST). Not affiliated with B3 or the CVM. Not investment advice.

Numbers on this page are live. Data version 2026-11-09-ancora-do-fre · page generated 2026-11-10 02:06 UTC. If this does not match /saude, you are reading a cached copy.