feat(ai): added MCP server discovery properties and refactored tool call handling

- Added mcpServerName and mcpToolName optional properties to tool definitions for MCP server discovery and tool name tracking.
- Changed aborted tool call handling to preserve existing tool results instead of replacing with synthetic 'aborted' results at turn boundaries.
- Extracted flushPendingToolCalls() and flushPendingAbortedToolCalls() helpers to consolidate orphaned tool call handling logic.
- Updated tool result handling to use message timestamps instead of Date.now() for synthetic results consistency.

packages/coding-agent/src/extensibility/custom-tools/types.ts

@@ -184,6 +184,10 @@ export interface CustomTool<TParams extends TSchema = TSchema, TDetails = any> {
 	hidden?: boolean;
 	/** If true, tool may stage deferred changes that require explicit resolve/discard. */
 	deferrable?: boolean;
+	/** MCP server name for discovery/search metadata when this tool fronts an MCP server. */
+	mcpServerName?: string;
+	/** Original MCP tool name for discovery/search metadata. */
+	mcpToolName?: string;
 	/**
 	 * Execute the tool.
 	 * @param toolCallId - Unique ID for this tool call

packages/coding-agent/src/extensibility/extensions/types.ts

@@ -300,6 +300,10 @@ export interface ToolDefinition<TParams extends TSchema = TSchema, TDetails = un
 	hidden?: boolean;
 	/** If true, tool may stage deferred changes that require explicit resolve/discard. */
 	deferrable?: boolean;
+	/** MCP server name for discovery/search metadata when this tool fronts an MCP server. */
+	mcpServerName?: string;
+	/** Original MCP tool name for discovery/search metadata. */
+	mcpToolName?: string;
 	/** Execute the tool. */
 	execute(
 		toolCallId: string,

packages/coding-agent/src/sdk.ts

@@ -422,6 +422,10 @@ function customToolToDefinition(tool: CustomTool): ToolDefinition {
 		label: tool.label,
 		description: tool.description,
 		parameters: tool.parameters,
+		hidden: tool.hidden,
+		deferrable: tool.deferrable,
+		mcpServerName: tool.mcpServerName,
+		mcpToolName: tool.mcpToolName,
 		execute: (toolCallId, params, signal, onUpdate, ctx) =>
 			tool.execute(toolCallId, params, onUpdate, createCustomToolContext(ctx), signal),
 		onSession: tool.onSession ? (event, ctx) => tool.onSession?.(event, createCustomToolContext(ctx)) : undefined,