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.

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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"

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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).

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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.

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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.

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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.

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License

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

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