diff --git a/src/resources/extensions/sf/tests/workflow-tool-executors.test.ts b/src/resources/extensions/sf/tests/workflow-tool-executors.test.ts
index 28d69b4d3..ef67b4716 100644
--- a/src/resources/extensions/sf/tests/workflow-tool-executors.test.ts
+++ b/src/resources/extensions/sf/tests/workflow-tool-executors.test.ts
@@ -9,7 +9,7 @@ import {
 } from "node:fs";
 import { tmpdir } from "node:os";
 import { join } from "node:path";
-import { test } from 'vitest';
+import { test } from "vitest";
 import type { PlanningMeetingRecord } from "../plan-quality.ts";
 import {
 	_getAdapter,
@@ -172,6 +172,36 @@ test("executeSummarySave persists artifact and returns computed path", async ()
 	}
 });
 
+test("executeSummarySave marks RESEARCH artifacts as terminal transitions", async () => {
+	const base = makeTmpBase();
+	try {
+		openTestDb(base);
+		const result = await inProjectDir(base, () =>
+			executeSummarySave(
+				{
+					milestone_id: "M001",
+					slice_id: "S01",
+					artifact_type: "RESEARCH",
+					content: "# Research\n\nfindings",
+				},
+				base,
+			),
+		);
+
+		assert.equal(result.details.operation, "save_summary");
+		assert.equal(result.details.artifact_type, "RESEARCH");
+		assert.equal(result.details.terminal_transition, true);
+		assert.equal(result.details.unit_type, "research");
+		assert.match(
+			result.content[0]?.text ?? "",
+			/Research unit terminal transition/,
+		);
+	} finally {
+		closeDatabase();
+		cleanup(base);
+	}
+});
+
 test("executeTaskComplete coerces string verificationEvidence entries", async () => {
 	const base = makeTmpBase();
 	try {
diff --git a/src/resources/extensions/sf/tools/workflow-tool-executors.ts b/src/resources/extensions/sf/tools/workflow-tool-executors.ts
index 498e7d9ab..d1da72d47 100644
--- a/src/resources/extensions/sf/tools/workflow-tool-executors.ts
+++ b/src/resources/extensions/sf/tools/workflow-tool-executors.ts
@@ -160,6 +160,28 @@ export async function executeSummarySave(
 			},
 			basePath,
 		);
+
+		// Terminal transition for research units: After successful RESEARCH artifact save,
+		// research units must terminate or become unable to call planning/milestone-generation tools.
+		// This prevents the dr-repo M008/S01 issue where research continued into planning.
+		if (params.artifact_type === "RESEARCH") {
+			return {
+				content: [
+					{
+						type: "text",
+						text: `Saved ${params.artifact_type} artifact to ${relativePath}\n\nResearch unit terminal transition: this research unit has completed its primary artifact and should terminate. Further planning or milestone-generation tools will be blocked.`,
+					},
+				],
+				details: {
+					operation: "save_summary",
+					path: relativePath,
+					artifact_type: params.artifact_type,
+					terminal_transition: true,
+					unit_type: "research",
+				},
+			};
+		}
+
 		return {
 			content: [
 				{