feat: refactor push notification config spec to align with a2a

.changeset/refactor-push-notification-config.md

@@ -0,0 +1,40 @@
+---
+"adcontextprotocol": patch
+---
+
+Redesign how AdCP handles push notifications for async tasks. The key change is separating **what data is sent** (AdCP's responsibility) from **how it's delivered** (protocol's responsibility).
+
+**Renamed:**
+
+- `webhook-payload.json` → `mcp-webhook-payload.json` (clarifies this envelope is MCP-specific)
+
+**Created:**
+
+- `async-response-data.json` - Union schema for all async response data types
+- Status-specific schemas for `working`, `input-required`, and `submitted` statuses
+
+**Deleted:**
+
+- Removed redundant `-async-response-completed.json` and `-async-response-failed.json` files (6 total)
+- For `completed`/`failed`, we now use the existing task response schemas directly
+
+**Before:** The webhook spec tried to be universal, which created confusion about how A2A's native push notifications fit in.
+
+**After:**
+
+- MCP uses `mcp-webhook-payload.json` as its envelope, with AdCP data in `result`
+- A2A uses its native `Task`/`TaskStatusUpdateEvent` messages, with AdCP data in `status.message.parts[].data`
+- Both use the **exact same data schemas** - only the envelope differs
+
+This makes it clear that AdCP only specifies the data layer, while each protocol handles delivery in its own way.
+
+**Schemas:**
+
+- `static/schemas/source/core/mcp-webhook-payload.json` (renamed + simplified)
+- `static/schemas/source/core/async-response-data.json` (new)
+- `static/schemas/source/media-buy/*-async-response-*.json` (6 deleted, 9 remain)
+
+- Clarified that both MCP and A2A use HTTP webhooks (A2A's is native to the spec, MCP's is AdCP-provided)
+- Fixed webhook trigger rules: webhooks fire for **all status changes** if `pushNotificationConfig` is provided and the task runs async
+- Added proper A2A webhook payload examples (`Task` vs `TaskStatusUpdateEvent`)
+- **Task Management** added to sidebar, it was missing

docs.json

@@ -63,8 +63,9 @@
                 ]
               },
               "docs/protocols/protocol-comparison",
-              "docs/protocols/envelope-examples",
-              "docs/protocols/context-management"
+              "docs/protocols/context-management",
+              "docs/protocols/task-management",
+              "docs/protocols/envelope-examples"
             ]
           },
           {