diff --git a/packages/agent/src/harness/types.ts b/packages/agent/src/harness/types.ts
index 64b27fdc..ea222d97 100644
--- a/packages/agent/src/harness/types.ts
+++ b/packages/agent/src/harness/types.ts
@@ -2,22 +2,35 @@ import type { ImageContent, Model, TextContent } from "@mariozechner/pi-ai";
 import type { AgentEvent, AgentMessage, AgentTool, ThinkingLevel } from "../index.js";
 import type { Session } from "./session/session.js";
 
+/** Model-visible skill loaded from a `SKILL.md` file or provided by an application. */
 export interface Skill {
+	/** Skill command name. */
 	name: string;
+	/** Short model-visible description of when to use the skill. */
 	description: string;
+	/** Full skill instructions. */
 	content: string;
+	/** Absolute path to the skill file. Used for model-visible location and resolving relative references. */
 	filePath: string;
+	/** Exclude this skill from model-visible skill lists while still allowing explicit application invocation. */
 	disableModelInvocation?: boolean;
 }
 
+/** Prompt template that can expand slash-command text before a prompt is sent. */
 export interface PromptTemplate {
+	/** Slash-command name without the leading `/`. */
 	name: string;
+	/** Optional description for command lists or autocomplete. */
 	description?: string;
+	/** Template content. Argument placeholders are expanded by `expandPromptTemplate`. */
 	content: string;
 }
 
+/** Resources made available to harness prompt expansion and system-prompt callbacks. */
 export interface AgentHarnessResources {
+	/** Prompt templates used to expand `/template args` input. */
 	promptTemplates?: PromptTemplate[];
+	/** Skills available to the model and explicit skill invocation. */
 	skills?: Skill[];
 }
 
diff --git a/packages/agent/test/scratch/simple.ts b/packages/agent/test/scratch/simple.ts
index 3d6592c6..4fb80d18 100644
--- a/packages/agent/test/scratch/simple.ts
+++ b/packages/agent/test/scratch/simple.ts
@@ -31,19 +31,17 @@ const agent = createAgentHarness({
 	session,
 	model: getModel("openai", "gpt-5.5"),
 	thinkingLevel: "low",
-	systemPrompt: ({ env, resources }) => {
-		console.log("Building system prompt");
-		return [
-			`You are a helpful assistant.`,
+	systemPrompt: ({ env, resources }) =>
+		[
+			"You are a helpful assistant.",
 			formatSkillsForSystemPrompt(resources.skills ?? []),
 			`Current working directory: ${env.cwd}`,
 		]
 			.filter((part) => part.length > 0)
-			.join("\n\n");
-	},
+			.join("\n\n"),
 	resources: {
-		promptTemplates: sourcedPromptTemplates.map((entry) => entry.promptTemplate),
-		skills: sourcedSkills.map((entry) => entry.skill),
+		promptTemplates: sourcedPromptTemplates.map(({ promptTemplate }) => promptTemplate),
+		skills: sourcedSkills.map(({ skill }) => skill),
 	},
 });