feat(harness): apply slim rules layer to named and SDD agents

Author: pablontiv

extensions/gentle-ai.ts

@@ -1970,8 +1970,17 @@ export const __testing = {
 		compactionPending = value;
 	},
 	getCompactionPending: () => compactionPending,
+	getAgentSlimRules: () => AGENT_SLIM_RULES,
 };
 
+const AGENT_SLIM_RULES = `## Gentle Agent Rules
+You operate inside the el Gentleman harness as a delegated agent.
+- Stay strictly within your assigned scope; do not expand the task.
+- Never run destructive commands (rm -rf on broad paths, git reset --hard, force push) without explicit instruction.
+- With tests present, provide TDD evidence: failing test first, then the implementation that makes it pass.
+- Do not spawn further orchestration; execute your role and return.
+- Report results honestly, including failures and skipped steps.`;
+
 export default function gentleAi(pi: ExtensionAPI): void {
 	function runSddPreflight(ctx: ExtensionContext): Promise<SddPreflightPreferences> {
 		return ensureSddPreflight(ctx, {
@@ -2047,7 +2056,7 @@ export default function gentleAi(pi: ExtensionAPI): void {
 			}), phase)}`
 			: "";
 		const gentlePrompt = isNamedAgent || isSddAgent
-			? ""
+			? `\n\n${AGENT_SLIM_RULES}`
 			: `\n\n${buildGentlePrompt(readPersonaMode(ctx.cwd))}`;
 		return {
 			systemPrompt: `${event.systemPrompt}${gentlePrompt}${sddPrompt}${nativeStatusPrompt}`,

tests/gentle-ai.test.ts

@@ -211,3 +211,21 @@ test("compaction flag resets when applyHarnessReminder builds fresh reminder", a
 	assert.equal(__testing.getCompactionPending(), false, "flag should be reset after applyHarnessReminder");
 	assert(result[0].content.includes("Context was just compacted"), "reminder should include compaction content");
 });
+
+test("agent slim rules contain expected content", async () => {
+	const slimRules = __testing.getAgentSlimRules();
+	assert(slimRules.includes("Gentle Agent Rules"), "should include header");
+	assert(slimRules.includes("Stay strictly within your assigned scope"), "should include scope rule");
+	assert(slimRules.includes("Never run destructive commands"), "should include safety rule");
+	assert(slimRules.includes("TDD evidence"), "should include TDD rule");
+	assert(slimRules.includes("Do not spawn further orchestration"), "should include no-orchestration rule");
+	assert(slimRules.includes("Report results honestly"), "should include honesty rule");
+});
+
+test("agent slim rules do not contain persona or orchestrator markers", async () => {
+	const slimRules = __testing.getAgentSlimRules();
+	assert(!slimRules.includes("el Gentleman Identity"), "slim rules must not contain identity contract");
+	assert(!slimRules.includes("Persona:"), "slim rules must not contain persona marker");
+	assert(!slimRules.includes("orchestrator.md"), "slim rules must not reference orchestrator");
+	assert(!slimRules.includes("Harness principles"), "slim rules must not contain harness principles");
+});

tests/runtime-harness.mjs

@@ -213,7 +213,10 @@ async function run() {
 			{ agentName: "worker", systemPrompt: "worker base" },
 			createCtx(promptCwd),
 		);
-		assert.equal(subagentPromptResult.systemPrompt, "worker base");
+		assert.match(subagentPromptResult.systemPrompt, /worker base/);
+		assert.match(subagentPromptResult.systemPrompt, /Gentle Agent Rules/);
+		assert.match(subagentPromptResult.systemPrompt, /Stay strictly within your assigned scope/);
+		assert.doesNotMatch(subagentPromptResult.systemPrompt, /el Gentleman Identity/);
 		assert.equal(
 			existsSync(join(promptCwd, ".pi", "agents", "sdd-apply.md")),
 			false,
@@ -504,11 +507,13 @@ async function run() {
 			{ agentName: "worker", systemPrompt: "worker base" },
 			ctx,
 		);
-		assert.equal(
+		assert.match(
 			workerPromptResult.systemPrompt,
-			"worker base",
-			"non-SDD subagents must not receive parent harness or SDD preflight prompts",
+			/worker base/,
+			"non-SDD subagents must receive slim rules but not parent harness or SDD preflight prompts",
 		);
+		assert.match(workerPromptResult.systemPrompt, /Gentle Agent Rules/);
+		assert.doesNotMatch(workerPromptResult.systemPrompt, /el Gentleman Identity/);
 	} finally {
 		await rm(lazySddCwd, { recursive: true, force: true });
 		await rm(globalModelsPath, { force: true });