# Cardog

> The system of record for the Canadian vehicle. A typed graph of automotive
> entities — every make, model, model year, recall and safety rating under a
> permanent `{domain}:{key}` ref — served as a REST API with an error
> contract designed for agents: an unknown ref is a 400 that names it and
> suggests the nearest match, never a fuzzy guess or a silently empty result.

The ref grammar is open source and free to hold: `npm install @cardog/entities`
validates, builds and types refs offline with no API call and no key.

## Docs

- [Full documentation](https://cardog.app/docs.md): every guide and the complete API reference as one markdown document — the one fetch that answers most questions.
- [Changelog](https://cardog.app/changelog.md): what shipped, newest first, as one markdown document.
- [Quickstart](https://cardog.app/docs/quickstart.md): Your first three calls: resolve free text to refs, then query with them.
- [The Vehicle Graph](https://cardog.app/docs/vehicle-graph.md): The data model behind every endpoint: typed entities, permanent refs, and the grains that connect a VIN to specs, recalls, and the live market.
- [The ref grammar](https://cardog.app/docs/ref-grammar.md): Hold the platform's identifier language offline: @cardog/entities validates, builds, and types refs with zero API calls — resolution is where the API begins.
- [Authentication](https://cardog.app/docs/authentication.md): API keys, both accepted headers, and the plan limits — straight from the code.
- [API conventions](https://cardog.app/docs/conventions.md): The mechanics every v2 group shares: encoding, response shape, null semantics, and the stability contract.
- [Credits & limits](https://cardog.app/docs/credits.md): One commercial currency across the platform: per-family rates, plan allowances, live budget headers, and what happens at the edge.
- [Errors](https://cardog.app/docs/errors.md): The v2 error envelope and a complete correction recipe for every well-known code.
- [Decode a Canadian VIN by API](https://cardog.app/docs/decode-canadian-vin.md): One VIN in, one identity card out — entity refs, VIN grains, and links, for 99.77% of Canadian VINs.
- [Understanding VINs](https://cardog.app/docs/vin.md): VIN structure and standards — what the 17 characters mean.
- [Market data](https://cardog.app/docs/market-data.md): Instruments, quotes, and the tape: how live listings become a priced, historied market grammar.
- [Transport Canada recall lookup by VIN, by API](https://cardog.app/docs/recalls.md): Per-VIN recall checks with citable authority — Transport Canada + NHTSA fused — and entity-scoped sweeps for fleets.
- [The Cardog MCP server: vehicle data as five tools](https://cardog.app/docs/mcp.md): Connect Claude, Cursor, VS Code, and any MCP client to Cardog vehicle data.
- [For agents](https://cardog.app/docs/agents.md): The agent-native contract: one-fetch docs, errors that instruct, resolve-first, link traversal, refs as memory, machine-readable pricing, and MCP.

## API reference

- [VIN](https://cardog.app/docs/reference/vin.md): Identity: VIN → refs, grains, links
- [Entities](https://cardog.app/docs/reference/entities.md): The registry: browse, resolve, dereference
- [Specs](https://cardog.app/docs/reference/specs.md): The attribute catalog + canonical spec sheets
- [Listings](https://cardog.app/docs/reference/listings.md): Ref-native listing search, counts, facets
- [Instruments](https://cardog.app/docs/reference/instruments.md): Market symbology + instrument cards
- [Quotes](https://cardog.app/docs/reference/quotes.md): The live book per instrument
- [Tape](https://cardog.app/docs/reference/tape.md): Prints + daily bars
- [Recalls](https://cardog.app/docs/reference/recalls.md): TC+NHTSA fused, ref-keyed compliance
- [Safety](https://cardog.app/docs/reference/safety.md): NCAP ratings + complaints
- [Platform](https://cardog.app/docs/reference/platform.md): Pricing, spec, meta

## Machine-readable

- [OpenAPI 3.1 spec](https://api.cardog.app/v2/openapi.json): the contract every response is validated against.
- [Rate card](https://api.cardog.app/v2/pricing): plans, per-family credit rates and packs as JSON, no auth required.
- [Agent Skill](https://cardog.app/skill.md): the same platform as a decision tree, installable in any skills-compatible harness (`npx skills add cardog.app`) — indexed at `/.well-known/agent-skills/index.json`.

Every HTML docs page has a markdown twin: append `.md`, or send
`Accept: text/markdown`.