API - CODEX AGENTS: MCP transport and real e2e smoke

docs/MCP_TOOLS_CONTRACT.md

@@ -8,6 +8,14 @@ The current Tasker / Plane fork does not expose a dedicated MCP server. It expos
 
 Codex should not call generic Tasker REST directly.
 
+Current implementation status:
+
+- Agent Gateway exposes `/mcp` as JSON-RPC over HTTP.
+- Implemented MCP methods: `initialize`, `ping`, `tools/list`, `tools/call`.
+- `tools/list` returns only tools allowed by the authenticated agent session scopes.
+- `tools/call` uses the same product runtime as REST tool endpoints.
+- Server-sent event streaming is intentionally not required for the first product slice.
+
 ## Authentication
 
 MCP clients authenticate to Agent Gateway with an opaque agent token.
@@ -18,6 +26,20 @@ Recommended transport options:
 - local stdio connector later if useful;
 - REST fallback for non-MCP clients.
 
+Current route:
+
+```text
+POST /mcp
+```
+
+Required request headers for authenticated tool calls:
+
+```text
+Authorization: Bearer <agent-token>
+Accept: application/json, text/event-stream
+MCP-Protocol-Version: 2025-06-18
+```
+
 Token rules:
 
 - token is opaque;