refactor(agent): make harness resources explicit

packages/agent/src/harness/agent-harness.ts

@@ -38,7 +38,7 @@ export class AgentHarness {
 	private steerQueue: UserMessage[] = [];
 	private followUpQueue: UserMessage[] = [];
 	private pendingSessionWrites: PendingSessionWrite[] = [];
-	private resources?: AgentHarnessOptions["resources"];
+	private resources: AgentHarnessResources;
 	private systemPrompt: AgentHarnessOptions["systemPrompt"];
 	private getApiKeyAndHeaders?: AgentHarnessOptions["getApiKeyAndHeaders"];
 	private tools = new Map<string, AgentTool>();
@@ -57,7 +57,7 @@ export class AgentHarness {
 		});
 		this.env = options.env;
 		this.session = options.session;
-		this.resources = options.resources;
+		this.resources = options.resources ?? {};
 		this.systemPrompt = options.systemPrompt;
 		this.getApiKeyAndHeaders = options.getApiKeyAndHeaders;
 		for (const tool of this.agent.state.tools) {
@@ -165,7 +165,7 @@ export class AgentHarness {
 
 	private async createTurnState(): Promise<AgentHarnessTurnState> {
 		const context = await this.session.buildContext();
-		const resources = typeof this.resources === "function" ? await this.resources() : (this.resources ?? {});
+		const resources = this.getResources();
 		const tools = [...this.tools.values()];
 		const activeTools = this.activeToolNames
 			.map((name) => this.tools.get(name))
@@ -578,8 +578,19 @@ export class AgentHarness {
 		this.agent.followUpMode = mode;
 	}
 
+	getResources(): AgentHarnessResources {
+		return {
+			skills: this.resources.skills?.slice(),
+			promptTemplates: this.resources.promptTemplates?.slice(),
+		};
+	}
+
 	async setResources(resources: AgentHarnessResources): Promise<void> {
-		this.resources = resources;
+		this.resources = {
+			skills: resources.skills?.slice(),
+			promptTemplates: resources.promptTemplates?.slice(),
+		};
+		await this.emitOwn({ type: "resources_update", resources: this.getResources() });
 	}
 
 	async setTools(tools: AgentTool[], activeToolNames?: string[]): Promise<void> {

packages/agent/src/harness/types.ts

@@ -410,6 +410,11 @@ export interface ThinkingLevelSelectEvent {
 	previousLevel: ThinkingLevel;
 }
 
+export interface ResourcesUpdateEvent {
+	type: "resources_update";
+	resources: AgentHarnessResources;
+}
+
 export type AgentHarnessOwnEvent =
 	| QueueUpdateEvent
 	| SavePointEvent
@@ -426,7 +431,8 @@ export type AgentHarnessOwnEvent =
 	| SessionBeforeTreeEvent
 	| SessionTreeEvent
 	| ModelSelectEvent
-	| ThinkingLevelSelectEvent;
+	| ThinkingLevelSelectEvent
+	| ResourcesUpdateEvent;
 
 export type AgentHarnessEvent = AgentEvent | AgentHarnessOwnEvent;
 
@@ -481,6 +487,7 @@ export type AgentHarnessEventResultMap = {
 	session_tree: undefined;
 	model_select: undefined;
 	thinking_level_select: undefined;
+	resources_update: undefined;
 	queue_update: undefined;
 	save_point: undefined;
 	abort: undefined;
@@ -565,7 +572,11 @@ export interface AgentHarnessOptions {
 	env: ExecutionEnv;
 	session: Session;
 	tools?: AgentTool[];
-	resources?: AgentHarnessResources | (() => AgentHarnessResources | Promise<AgentHarnessResources>);
+	/**
+	 * Concrete resources available to explicit invocation methods and system-prompt callbacks.
+	 * Applications own loading/reloading resources and should call `setResources()` with new values.
+	 */
+	resources?: AgentHarnessResources;
 	systemPrompt?:
 		| string
 		| ((context: {