# QuarterCharts

> Grounded financial data + visualization grammar from SEC EDGAR XBRL filings for every US-listed public company. AI-agent-ready with citation provenance on every datapoint.

QuarterCharts ships a Model Context Protocol (MCP) server so AI agents like Claude Desktop, ChatGPT custom GPTs, and open-source agent frameworks can discover and call our financial-data tools natively — no HTML scraping, no API client to wire up.

## Primary AI surface

- [MCP server (JSON-RPC 2.0)](https://api.quartercharts.com/mcp): primary callable surface. POST JSON-RPC envelopes; tools/list returns the 13 tool descriptors with input schemas (7 core + 4 Phase 1A: segments, pension, debt schedule, split-adjusted share count + 2 Phase 1B: resolve_entity, resolve_period — deterministic entity + fiscal-period disambiguation, the recommended first calls). Bearer JWT auth (mint at https://us.quartercharts.com/dashboard/api-keys) or anonymous (free-tier ticker allow-list only).
- [MCP manifest](https://api.quartercharts.com/mcp/manifest): server descriptor for registries.
- [MCP tools/list](https://api.quartercharts.com/mcp/tools): HTTP-GET variant of tools/list for registries that prefer REST.
- [OpenAI plugin manifest](https://api.quartercharts.com/.well-known/ai-plugin.json): legacy discovery format, same endpoint underneath.

## Public REST API

- [REST API docs](https://us.quartercharts.com/docs/api): human-readable reference for the same data with code examples in curl, Python, JavaScript, Excel, and Claude Desktop MCP config.
- [OpenAPI / Swagger](https://api.quartercharts.com/docs): machine-readable OpenAPI 3.1 schema for every v1 endpoint.
- [Pricing + tiers](https://us.quartercharts.com/api): free (7 tickers) → Pro ($299) → Business ($999) → Enterprise.

## Provenance

Every value returned by both the REST API and the MCP server includes:

- `qc_metric_provenance` — human-readable string identifying QuarterCharts + the upstream source (e.g. "QC API v1, derived from SEC EDGAR 10-K + 10-Q structured XBRL")
- `last_updated_iso` — ISO-8601 timestamp from the ingestion pipeline
- `qc_session_id` — UUID4 per request for trace correlation
- `qc_tier_returned` / `qc_caller_plan` — which content variant + caller's resolved plan

Contact: info@quartercharts.com