# Synapse Discovery

> Point-in-time, survivorship-free financial data — equity prices, SEC fundamentals,
> fund holdings (SEC N-PORT), and FRED macro. A typed REST API and a native Model
> Context Protocol (MCP) server that AI agents and backtests can both trust.

## Model Context Protocol (for AI agents)

- MCP endpoint: https://synapsediscovery.io/mcp/jsonrpc — JSON-RPC 2.0 over Streamable HTTP (protocol 2025-06-18, single POST, no SSE).
- No API key needed to start: POST an `initialize` and read the `Mcp-Session-Id` response header (anonymous free tier). Verify an email in-browser for the full free tier (100 calls/day), or send `X-API-Key: sd_live_...` for a paid plan.
- Connect with Claude: `claude mcp add --transport http synapse https://synapsediscovery.io/mcp/jsonrpc`
- Discovery: https://synapsediscovery.io/mcp · Tool catalog: https://synapsediscovery.io/mcp/tools · Manifest: https://synapsediscovery.io/.well-known/mcp.json
- Flow: `initialize` → `tools/list` → `tools/call`. Resend `Mcp-Session-Id` on every request.
- One-shot: with `X-API-Key` you can SKIP the handshake entirely — POST a single `tools/call` (no initialize, no session header). The handshake is only needed for the keyless anonymous tier.
- Don't know a series ID? Call `search_economic_series("keywords")` to find it by name. `get_quota` reports your remaining budget.

## REST API

- API base: https://synapsediscovery.io/api/v1
- Docs: https://synapsediscovery.io/docs
- Auth: `X-API-Key: sd_live_...` header (free tier: 100 calls/day).

## What's in the data

- US equities: daily prices (incl. delisted/dead stocks — survivorship-free), SEC XBRL fundamentals.
- Funds (ETF + mutual fund): NAV history, SEC profiles/fees, computed ratings, full point-in-time holdings from SEC N-PORT.
- Macro: 900+ curated FRED series, Treasury yield curves, market context — all point-in-time.

## Notes

- Point-in-time semantics: query data as it was known on a historical date (for honest backtests).
- The `synapse_star_rating` is our own (within-category Sharpe percentile), not Morningstar.