Clix A2A Agent
Agent2Agent (A2A) protocol surface: a public agent card at https://api.clix.so/.well-known/agent-card.json (0.3.0 shape by default, 1.0 shape under the A2A-Version: 1.0 header; graded conformant) and a JSON-RPC 2.0 endpoint at POST https://api.clix.so/a2a authenticated with a secret X-API-Key (clix_sk_ prefix). Four built-in skills — create-user, track-event, send-push-notification, trigger-campaign — each a projection of one REST operation, executed as tasks with SendMessage / SendStreamingMessage (SSE), GetTask, ListTasks (cursor pagination), CancelTask, task webhooks (CreateTaskPushNotificationConfig) and an authenticated extended card. Adds what the REST layer lacks: X-Clix-Idempotency-Key replay protection with 409 semantics and X-Request-ID tracing. The anonymous endpoint answers 401 Missing API key.