feat: implement AfterTool tail tool calls (#18486)

docs/hooks/reference.md

@@ -98,6 +98,8 @@ and parameter rewriting.
   - `tool_name`: (`string`) The name of the tool being called.
   - `tool_input`: (`object`) The raw arguments generated by the model.
   - `mcp_context`: (`object`) Optional metadata for MCP-based tools.
+  - `original_request_name`: (`string`) The original name of the tool being
+    called, if this is a tail tool call.
 - **Relevant Output Fields**:
   - `decision`: Set to `"deny"` (or `"block"`) to prevent the tool from
     executing.
@@ -120,12 +122,18 @@ hiding sensitive output from the agent.
   - `tool_response`: (`object`) The result containing `llmContent`,
     `returnDisplay`, and optional `error`.
   - `mcp_context`: (`object`)
+  - `original_request_name`: (`string`) The original name of the tool being
+    called, if this is a tail tool call.
 - **Relevant Output Fields**:
   - `decision`: Set to `"deny"` to hide the real tool output from the agent.
   - `reason`: Required if denied. This text **replaces** the tool result sent
     back to the model.
   - `hookSpecificOutput.additionalContext`: Text that is **appended** to the
     tool result for the agent.
+  - `hookSpecificOutput.tailToolCallRequest`: (`{ name: string, args: object }`)
+    A request to execute another tool immediately after this one. The result of
+    this "tail call" will replace the original tool's response. Ideal for
+    programmatic tool routing.
   - `continue`: Set to `false` to **kill the entire agent loop** immediately.
 - **Exit Code 2 (Block Result)**: Hides the tool result. Uses `stderr` as the
   replacement content sent to the agent. **The turn continues.**