> ## Documentation Index
> Fetch the complete documentation index at: https://docs.barker.money/llms.txt
> Use this file to discover all available pages before exploring further.

# API Changelog

> Changes to Barker's public data API and the x402 agent gateway. Additive-only: existing response fields never disappear, anchor field types never change.

## Compatibility policy

Barker's public data API follows a strict **additive-only** rule:

* Existing response fields are never removed; deprecated fields stop being populated but keep their keys.
* Anchor field types (`pool_uid`, `protocol_uid`, `asset_symbol`, APY/TVL numerics) never change type.
* New fields and new endpoints may appear at any time — parse defensively, ignore unknown keys.
* Response shapes are guarded by contract tests in CI against the live API.

## 2026-07-02 — Resource-domain endpoints & x402 gateway v2 catalog

**New canonical endpoints** (free tier, no auth, 30 req/min per IP):

| Endpoint                   | Description                                                  |
| -------------------------- | ------------------------------------------------------------ |
| `GET /api/defi/vaults`     | Ranked stablecoin yield pools (500+ protocols)               |
| `GET /api/defi/protocols`  | Protocol-level aggregates                                    |
| `GET /api/defi/campaigns`  | On-chain campaign listings                                   |
| `GET /api/defi/lending`    | Supply-side lending pools                                    |
| `GET /api/market/overview` | Market snapshot                                              |
| `GET /api/market/trend`    | Historical APY vs US Treasury                                |
| `GET /api/cex/*`           | CEX venue/product/campaign facts (7 endpoints, now key-free) |
| `GET /api/llms.txt`        | Agent discovery file (also at `api.barker.money/llms.txt`)   |

**Retired**: the `/api/public/v1/*` surface returns `410 Gone` with a machine-readable
migration pointer (`error.new_base` + endpoint map). No compatibility window.

**x402 agent gateway** (`mcp.barker.money`) expanded from 3 to **12 paid tools**:
the flagship `barker_yield_advisor` ($0.01/call — ranked picks with reasons and risk flags), `barker_cex_campaigns`, `barker_campaign_radar`, `barker_campaign_detail`, `barker_pool_detail`, `barker_pool_history`, `barker_pool_search`, `barker_exchange_paths`, `barker_crosschain_routes` (judgment tier, $0.005/call),
plus the original three factual tools (\$0.001/call). Payment via x402
(USDT0 / USDC across X Layer, Base, Ethereum, Polygon, Arbitrum). HTTP 402
challenge on first call carries the full offer.

**Units note**: free-tier REST endpoints return APY as decimals (`0.045` = 4.5%);
gateway tool payloads use percent (`4.5` = 4.5%) and say so in each tool description.