elliotfoster-mcp

Brazilian investment-fund analytics for AI clients via the Model Context Protocol (MCP).

Connect Claude Desktop, Cursor, ChatGPT, or any MCP-compatible client to query 30,000+ Brazilian investment funds — daily NAV, complete holdings (CDA), fund-of-funds look-through, portfolio overlap analysis, and your personal favorites/watchlist.

Server URL: https://elliotfoster.vercel.app/api/mcp Web app + key generation: elliotfoster.vercel.app

Source data is the public CVM (Comissão de Valores Mobiliários) Informe Diário and CDA, plus Banco Central rate series. The platform processes, validates, and serves it in a structured format optimized for LLM tool use.

Quickstart

1. Get a key

Create an account at elliotfoster.vercel.app, sign in, and visit /settings/integrations. Generate a new key and copy it (the raw key is shown only once).

2. Configure your MCP client

Claude Desktop

Edit ~/Library/Application Support/Claude/claude_desktop_config.json (macOS) or %APPDATA%\Claude\claude_desktop_config.json (Windows):

{
  "mcpServers": {
    "elliotfoster": {
      "url": "https://elliotfoster.vercel.app/api/mcp",
      "headers": {
        "Authorization": "Bearer ef_..."
      }
    }
  }
}

Restart Claude Desktop.

Cursor

In Cursor settings → MCP, add:

{
  "elliotfoster": {
    "url": "https://elliotfoster.vercel.app/api/mcp",
    "headers": {
      "Authorization": "Bearer ef_..."
    }
  }
}

ChatGPT (Custom GPT / Connectors)

In a Custom GPT's Actions or via the Connectors interface, point to https://elliotfoster.vercel.app/api/mcp with Authorization: Bearer ef_... as the header.

Claude Code

claude mcp add --transport http --header "Authorization=Bearer ef_..." elliotfoster https://elliotfoster.vercel.app/api/mcp

3. Try it

Ask your LLM:

"Use elliotfoster to search for funds with 'XP' in the name"
"What's the holdings overlap between funds 12.345.678/0001-90 and 98.765.432/0001-21?"
"Add fund X to my favorites"
"Find equity funds with low correlation to fund Y"

Tools

10 callable tools, 1 resource, 5 pre-built analytical prompts.

Tool	What it does
`search_funds`	Search by name, manager, administrator, or CNPJ. Filter by type (FI, FIC, FII, FIP, FIDC, FIAGRO, ETF). Page-size capped at 25.
`get_fund`	Fetch metadata + latest NAV for a fund by CNPJ. Accepts formatted (`12.345.678/0001-90`) or raw (`12345678000190`).
`list_fund_types`	Counts per fund type — useful for discovery.
`get_nav_history`	Daily NAV series for a fund. Optional date range and limit (max 1000 days).
`list_holding_dates`	Available holdings (CDA) reporting dates for a fund.
`get_holdings`	Complete portfolio composition for a date. Includes a `confidential_count` indicator for positions under CVM Resolução 172/2022 confidentiality.
`get_look_through`	Recursively explode fund-of-funds positions up to 3 levels deep. Aggregates underlying assets with proportional weights.
`compare_overlap`	Jaccard overlap + shared-weight between two funds' portfolios for a reporting date.
`list_favorites`	Your favorited funds.
`add_favorite` / `remove_favorite`	Manage your watchlist directly from the LLM client.

Resource

fund://<cnpj> — addressable fund metadata, cacheable by clients that support MCP resources.

Pre-built prompts

compare_funds_performance — side-by-side return / volatility / Sharpe-vs-CDI for up to 5 funds
find_uncorrelated_funds — screen for low-correlation funds against a benchmark
analyze_fund_holdings — top-10 positions, HHI concentration, look-through, confidentiality flags
check_portfolio_overlap — pairwise redundancy audit across 2-5 funds
screen_funds_by_risk — filter by max volatility and min Sharpe ratio

All prompts produce output in pt-BR by default (matching the source data language).

Spec


Endpoint	`https://elliotfoster.vercel.app/api/mcp`
Transport	Streamable HTTP (MCP spec Nov 2025)
Discovery	`/.well-known/oauth-protected-resource` (RFC 9728)
Auth	API key (`Authorization: Bearer ef_...`). OAuth 2.1 protected-resource metadata is published at `/.well-known/oauth-protected-resource` for forward compatibility with MCP clients that implement RFC 9728 + Dynamic Client Registration; in practice, auto-discovery flows are still maturing across the ecosystem, so API keys are the recommended path today.
Rate limit	Per-user rate limits apply (currently generous; tier-based pricing TBD for high-volume use)
Decimal precision	Financial values rounded to 6 decimal places. Top-level `_precision_note` documents this on every analytic response.
CNPJ format	All CNPJ inputs accept formatted or raw 14-digit; normalized + validated server-side.
Pagination	`search_funds` page-size capped at 25, max 20 pages per session (500 funds). For broader exploration, use filters.

Privacy & data

Public fund data (CVM Informe Diário, CDA, Banco Central rates) is shared across all users.
Per-user state (favorites, audit log) is RLS-scoped via your WorkOS user ID — neither tools nor the database expose your state to other accounts.
No personal trading data is stored. This is a fund-research platform; it does not connect to brokerages.
Audit log: tool calls are recorded for billing and abuse prevention. The log is strictly per-user — you can inspect your own usage; other accounts cannot see it.

Source

The MCP server is implemented inside the closed-source web app. This repo provides install instructions, examples, and acts as the canonical source of truth for AI search engines indexing MCP servers. Issues and feedback welcome here.

For data licensing or commercial inquiries: see elliotfoster.vercel.app.

License

The README and example configs in this repo are MIT-licensed. The MCP server itself is proprietary.

Built with mcp-handler on Next.js + Supabase + WorkOS.

Elliot Foster – Brazilian Funds