diff --git a/.changeset/patch-stable-island-markers.md b/.changeset/patch-stable-island-markers.md
new file mode 100644
index 0000000000..1a7c22b2d1
--- /dev/null
+++ b/.changeset/patch-stable-island-markers.md
@@ -0,0 +1,5 @@
+---
+"gh-aw": patch
+---
+
+Ensure update_body island markers use workflow-id so repeated runs reuse the same island instead of appending new ones.
diff --git a/actions/setup/js/fuzz_update_body_harness.cjs b/actions/setup/js/fuzz_update_body_harness.cjs
index 30396dfa26..19c8ea79be 100644
--- a/actions/setup/js/fuzz_update_body_harness.cjs
+++ b/actions/setup/js/fuzz_update_body_harness.cjs
@@ -23,10 +23,10 @@ const { updateBody } = require("./update_pr_description_helpers.cjs");
  * @param {string} operation - Operation type: "append", "prepend", "replace", or "replace-island"
  * @param {string} workflowName - Name of the workflow
  * @param {string} runUrl - URL of the workflow run
- * @param {number} runId - Workflow run ID
+ * @param {string} workflowId - Workflow ID (stable identifier across runs)
  * @returns {{result: string, error: string | null}} Result object
  */
-function testUpdateBody(currentBody, newContent, operation, workflowName, runUrl, runId) {
+function testUpdateBody(currentBody, newContent, operation, workflowName, runUrl, workflowId) {
   try {
     const result = updateBody({
       currentBody,
@@ -34,7 +34,7 @@ function testUpdateBody(currentBody, newContent, operation, workflowName, runUrl
       operation,
       workflowName,
       runUrl,
-      runId,
+      workflowId,
     });
     return { result, error: null };
   } catch (err) {
@@ -55,9 +55,9 @@ if (require.main === module) {
 
   process.stdin.on("end", () => {
     try {
-      // Parse input as JSON: { currentBody, newContent, operation, workflowName, runUrl, runId }
-      const { currentBody, newContent, operation, workflowName, runUrl, runId } = JSON.parse(input);
-      const result = testUpdateBody(currentBody || "", newContent || "", operation || "append", workflowName || "Test Workflow", runUrl || "https://github.com/test/actions/runs/123", runId || 123);
+      // Parse input as JSON: { currentBody, newContent, operation, workflowName, runUrl, workflowId }
+      const { currentBody, newContent, operation, workflowName, runUrl, workflowId } = JSON.parse(input);
+      const result = testUpdateBody(currentBody || "", newContent || "", operation || "append", workflowName || "Test Workflow", runUrl || "https://github.com/test/actions/runs/123", workflowId || "test-workflow");
       process.stdout.write(JSON.stringify(result));
       process.exit(0);
     } catch (err) {
diff --git a/actions/setup/js/update_issue.cjs b/actions/setup/js/update_issue.cjs
index 3c7af9d8fa..b1bcfc6b4f 100644
--- a/actions/setup/js/update_issue.cjs
+++ b/actions/setup/js/update_issue.cjs
@@ -52,6 +52,7 @@ async function executeIssueUpdate(github, context, issueNumber, updateData) {
 
     // Get workflow run URL for AI attribution
     const workflowName = process.env.GH_AW_WORKFLOW_NAME || "GitHub Agentic Workflow";
+    const workflowId = process.env.GH_AW_WORKFLOW_ID || "";
     const runUrl = `${context.serverUrl}/${context.repo.owner}/${context.repo.repo}/actions/runs/${context.runId}`;
 
     // Use helper to update body (handles all operations including replace)
@@ -61,7 +62,7 @@ async function executeIssueUpdate(github, context, issueNumber, updateData) {
       operation,
       workflowName,
       runUrl,
-      runId: context.runId,
+      workflowId,
       includeFooter, // Pass footer flag to helper
     });
 
diff --git a/actions/setup/js/update_issue.test.cjs b/actions/setup/js/update_issue.test.cjs
index 3eb1bbf892..27b787999f 100644
--- a/actions/setup/js/update_issue.test.cjs
+++ b/actions/setup/js/update_issue.test.cjs
@@ -52,6 +52,7 @@ describe("update_issue.cjs - footer support", () => {
 
     // Reset environment variables
     process.env.GH_AW_WORKFLOW_NAME = "Test Workflow";
+    process.env.GH_AW_WORKFLOW_ID = "test-workflow";
 
     // Reset mock implementations
     mockGithub.rest.issues.get.mockResolvedValue({
@@ -209,17 +210,17 @@ describe("update_issue.cjs - footer support", () => {
       });
 
       const newContent = "Island content";
-      const expectedBody = `Original content\n\n---\n\n<!-- gh-aw-island-start:12345 -->\n${newContent}\n\n> AI generated by [Test Workflow](https://github.com/testowner/testrepo/actions/runs/12345)\n<!-- gh-aw-island-end:12345 -->`;
+      const expectedBody = `Original content\n\n---\n\n<!-- gh-aw-island-start:test-workflow -->\n${newContent}\n\n> AI generated by [Test Workflow](https://github.com/testowner/testrepo/actions/runs/12345)\n<!-- gh-aw-island-end:test-workflow -->`;
 
       expect(expectedBody).toContain("Original content");
       expect(expectedBody).toContain("Island content");
-      expect(expectedBody).toContain("<!-- gh-aw-island-start:12345 -->");
-      expect(expectedBody).toContain("<!-- gh-aw-island-end:12345 -->");
+      expect(expectedBody).toContain("<!-- gh-aw-island-start:test-workflow -->");
+      expect(expectedBody).toContain("<!-- gh-aw-island-end:test-workflow -->");
       expect(expectedBody).toContain("> AI generated by");
     });
 
     it("should replace existing island content", async () => {
-      const existingBody = "Before\n<!-- gh-aw-island-start:12345 -->\nOld island\n<!-- gh-aw-island-end:12345 -->\nAfter";
+      const existingBody = "Before\n<!-- gh-aw-island-start:test-workflow -->\nOld island\n<!-- gh-aw-island-end:test-workflow -->\nAfter";
       mockGithub.rest.issues.get.mockResolvedValueOnce({
         data: {
           number: 100,
@@ -230,7 +231,7 @@ describe("update_issue.cjs - footer support", () => {
       });
 
       const newContent = "New island";
-      const expectedBody = `Before\n<!-- gh-aw-island-start:12345 -->\n${newContent}\n\n> AI generated by [Test Workflow](https://github.com/testowner/testrepo/actions/runs/12345)\n<!-- gh-aw-island-end:12345 -->\nAfter`;
+      const expectedBody = `Before\n<!-- gh-aw-island-start:test-workflow -->\n${newContent}\n\n> AI generated by [Test Workflow](https://github.com/testowner/testrepo/actions/runs/12345)\n<!-- gh-aw-island-end:test-workflow -->\nAfter`;
 
       expect(expectedBody).toContain("Before");
       expect(expectedBody).toContain("After");
@@ -456,17 +457,17 @@ describe("update_issue.cjs - footer support", () => {
       });
 
       const newContent = "New island";
-      // Should append because island with run ID 12345 doesn't exist
-      const expectedBody = `${existingBody}\n\n---\n\n<!-- gh-aw-island-start:12345 -->\n${newContent}\n\n> AI generated by [Test Workflow](https://github.com/testowner/testrepo/actions/runs/12345)\n<!-- gh-aw-island-end:12345 -->`;
+      // Should append because island with workflow test-workflow doesn't exist
+      const expectedBody = `${existingBody}\n\n---\n\n<!-- gh-aw-island-start:test-workflow -->\n${newContent}\n\n> AI generated by [Test Workflow](https://github.com/testowner/testrepo/actions/runs/12345)\n<!-- gh-aw-island-end:test-workflow -->`;
 
       expect(expectedBody).toContain("Other island");
       expect(expectedBody).toContain("New island");
       expect(expectedBody).toContain("<!-- gh-aw-island-start:99999 -->");
-      expect(expectedBody).toContain("<!-- gh-aw-island-start:12345 -->");
+      expect(expectedBody).toContain("<!-- gh-aw-island-start:test-workflow -->");
     });
 
     it("should preserve content outside island when replacing", async () => {
-      const existingBody = "# Title\n\n<!-- gh-aw-island-start:12345 -->\nOld\n<!-- gh-aw-island-end:12345 -->\n\n## Footer";
+      const existingBody = "# Title\n\n<!-- gh-aw-island-start:test-workflow -->\nOld\n<!-- gh-aw-island-end:test-workflow -->\n\n## Footer";
       mockGithub.rest.issues.get.mockResolvedValueOnce({
         data: {
           number: 100,
@@ -477,7 +478,7 @@ describe("update_issue.cjs - footer support", () => {
       });
 
       const newContent = "Updated content";
-      const expectedBody = `# Title\n\n<!-- gh-aw-island-start:12345 -->\n${newContent}\n\n> AI generated by [Test Workflow](https://github.com/testowner/testrepo/actions/runs/12345)\n<!-- gh-aw-island-end:12345 -->\n\n## Footer`;
+      const expectedBody = `# Title\n\n<!-- gh-aw-island-start:test-workflow -->\n${newContent}\n\n> AI generated by [Test Workflow](https://github.com/testowner/testrepo/actions/runs/12345)\n<!-- gh-aw-island-end:test-workflow -->\n\n## Footer`;
 
       expect(expectedBody).toContain("# Title");
       expect(expectedBody).toContain("## Footer");
diff --git a/actions/setup/js/update_pr_description_helpers.cjs b/actions/setup/js/update_pr_description_helpers.cjs
index c4d993b13c..a666548229 100644
--- a/actions/setup/js/update_pr_description_helpers.cjs
+++ b/actions/setup/js/update_pr_description_helpers.cjs
@@ -22,31 +22,31 @@ function buildAIFooter(workflowName, runUrl) {
 
 /**
  * Build the island start marker for replace-island mode
- * @param {number} runId - Workflow run ID
+ * @param {string} workflowId - Workflow ID (stable identifier across runs)
  * @returns {string} Island start marker
  */
-function buildIslandStartMarker(runId) {
-  return `<!-- gh-aw-island-start:${runId} -->`;
+function buildIslandStartMarker(workflowId) {
+  return `<!-- gh-aw-island-start:${workflowId} -->`;
 }
 
 /**
  * Build the island end marker for replace-island mode
- * @param {number} runId - Workflow run ID
+ * @param {string} workflowId - Workflow ID (stable identifier across runs)
  * @returns {string} Island end marker
  */
-function buildIslandEndMarker(runId) {
-  return `<!-- gh-aw-island-end:${runId} -->`;
+function buildIslandEndMarker(workflowId) {
+  return `<!-- gh-aw-island-end:${workflowId} -->`;
 }
 
 /**
  * Find and extract island content from body
  * @param {string} body - The body content to search
- * @param {number} runId - Workflow run ID
+ * @param {string} workflowId - Workflow ID (stable identifier across runs)
  * @returns {{found: boolean, startIndex: number, endIndex: number}} Island location info
  */
-function findIsland(body, runId) {
-  const startMarker = buildIslandStartMarker(runId);
-  const endMarker = buildIslandEndMarker(runId);
+function findIsland(body, workflowId) {
+  const startMarker = buildIslandStartMarker(workflowId);
+  const endMarker = buildIslandEndMarker(workflowId);
 
   const startIndex = body.indexOf(startMarker);
   if (startIndex === -1) {
@@ -70,12 +70,12 @@ function findIsland(body, runId) {
  * @param {string} params.operation - Operation type: "append", "prepend", "replace", or "replace-island"
  * @param {string} params.workflowName - Name of the workflow
  * @param {string} params.runUrl - URL of the workflow run
- * @param {number} params.runId - Workflow run ID
+ * @param {string} params.workflowId - Workflow ID (stable identifier across runs)
  * @param {boolean} [params.includeFooter=true] - Whether to include AI-generated footer (default: true)
  * @returns {string} Updated body content
  */
 function updateBody(params) {
-  const { currentBody, newContent, operation, workflowName, runUrl, runId, includeFooter = true } = params;
+  const { currentBody, newContent, operation, workflowName, runUrl, workflowId, includeFooter = true } = params;
   const aiFooter = includeFooter ? buildAIFooter(workflowName, runUrl) : "";
 
   if (operation === "replace") {
@@ -85,14 +85,14 @@ function updateBody(params) {
   }
 
   if (operation === "replace-island") {
-    // Try to find existing island for this run ID
-    const island = findIsland(currentBody, runId);
+    // Try to find existing island for this workflow ID
+    const island = findIsland(currentBody, workflowId);
 
     if (island.found) {
       // Replace the island content
-      core.info(`Operation: replace-island (updating existing island for run ${runId})`);
-      const startMarker = buildIslandStartMarker(runId);
-      const endMarker = buildIslandEndMarker(runId);
+      core.info(`Operation: replace-island (updating existing island for workflow ${workflowId})`);
+      const startMarker = buildIslandStartMarker(workflowId);
+      const endMarker = buildIslandEndMarker(workflowId);
       const islandContent = `${startMarker}\n${newContent}${aiFooter}\n${endMarker}`;
 
       const before = currentBody.substring(0, island.startIndex);
@@ -100,9 +100,9 @@ function updateBody(params) {
       return before + islandContent + after;
     } else {
       // Island not found, fall back to append mode
-      core.info(`Operation: replace-island (island not found for run ${runId}, falling back to append)`);
-      const startMarker = buildIslandStartMarker(runId);
-      const endMarker = buildIslandEndMarker(runId);
+      core.info(`Operation: replace-island (island not found for workflow ${workflowId}, falling back to append)`);
+      const startMarker = buildIslandStartMarker(workflowId);
+      const endMarker = buildIslandEndMarker(workflowId);
       const islandContent = `${startMarker}\n${newContent}${aiFooter}\n${endMarker}`;
       const appendSection = `\n\n---\n\n${islandContent}`;
       return currentBody + appendSection;
diff --git a/actions/setup/js/update_pr_description_helpers.test.cjs b/actions/setup/js/update_pr_description_helpers.test.cjs
index 61888854ed..20c41561f2 100644
--- a/actions/setup/js/update_pr_description_helpers.test.cjs
+++ b/actions/setup/js/update_pr_description_helpers.test.cjs
@@ -34,64 +34,64 @@ describe("update_pr_description_helpers.cjs", () => {
   });
 
   describe("buildIslandStartMarker", () => {
-    it("should build island start marker with run ID", () => {
-      const marker = buildIslandStartMarker(12345);
-      expect(marker).toBe("<!-- gh-aw-island-start:12345 -->");
+    it("should build island start marker with workflow ID", () => {
+      const marker = buildIslandStartMarker("test-workflow");
+      expect(marker).toBe("<!-- gh-aw-island-start:test-workflow -->");
     });
 
-    it("should handle different run IDs", () => {
-      expect(buildIslandStartMarker(1)).toBe("<!-- gh-aw-island-start:1 -->");
-      expect(buildIslandStartMarker(999999)).toBe("<!-- gh-aw-island-start:999999 -->");
+    it("should handle different workflow IDs", () => {
+      expect(buildIslandStartMarker("workflow-1")).toBe("<!-- gh-aw-island-start:workflow-1 -->");
+      expect(buildIslandStartMarker("my-awesome-workflow")).toBe("<!-- gh-aw-island-start:my-awesome-workflow -->");
     });
   });
 
   describe("buildIslandEndMarker", () => {
-    it("should build island end marker with run ID", () => {
-      const marker = buildIslandEndMarker(12345);
-      expect(marker).toBe("<!-- gh-aw-island-end:12345 -->");
+    it("should build island end marker with workflow ID", () => {
+      const marker = buildIslandEndMarker("test-workflow");
+      expect(marker).toBe("<!-- gh-aw-island-end:test-workflow -->");
     });
 
-    it("should handle different run IDs", () => {
-      expect(buildIslandEndMarker(1)).toBe("<!-- gh-aw-island-end:1 -->");
-      expect(buildIslandEndMarker(999999)).toBe("<!-- gh-aw-island-end:999999 -->");
+    it("should handle different workflow IDs", () => {
+      expect(buildIslandEndMarker("workflow-1")).toBe("<!-- gh-aw-island-end:workflow-1 -->");
+      expect(buildIslandEndMarker("my-awesome-workflow")).toBe("<!-- gh-aw-island-end:my-awesome-workflow -->");
     });
   });
 
   describe("findIsland", () => {
     it("should find island when both markers are present", () => {
-      const body = "Before\n<!-- gh-aw-island-start:123 -->\nIsland content\n<!-- gh-aw-island-end:123 -->\nAfter";
-      const result = findIsland(body, 123);
+      const body = "Before\n<!-- gh-aw-island-start:test-workflow -->\nIsland content\n<!-- gh-aw-island-end:test-workflow -->\nAfter";
+      const result = findIsland(body, "test-workflow");
       expect(result.found).toBe(true);
       expect(result.startIndex).toBeGreaterThanOrEqual(0);
       expect(result.endIndex).toBeGreaterThan(result.startIndex);
     });
 
     it("should not find island when start marker is missing", () => {
-      const body = "Before\nIsland content\n<!-- gh-aw-island-end:123 -->\nAfter";
-      const result = findIsland(body, 123);
+      const body = "Before\nIsland content\n<!-- gh-aw-island-end:test-workflow -->\nAfter";
+      const result = findIsland(body, "test-workflow");
       expect(result.found).toBe(false);
       expect(result.startIndex).toBe(-1);
       expect(result.endIndex).toBe(-1);
     });
 
     it("should not find island when end marker is missing", () => {
-      const body = "Before\n<!-- gh-aw-island-start:123 -->\nIsland content\nAfter";
-      const result = findIsland(body, 123);
+      const body = "Before\n<!-- gh-aw-island-start:test-workflow -->\nIsland content\nAfter";
+      const result = findIsland(body, "test-workflow");
       expect(result.found).toBe(false);
       expect(result.startIndex).toBe(-1);
       expect(result.endIndex).toBe(-1);
     });
 
-    it("should not find island when run ID does not match", () => {
-      const body = "Before\n<!-- gh-aw-island-start:123 -->\nIsland content\n<!-- gh-aw-island-end:123 -->\nAfter";
-      const result = findIsland(body, 456);
+    it("should not find island when workflow ID does not match", () => {
+      const body = "Before\n<!-- gh-aw-island-start:workflow-a -->\nIsland content\n<!-- gh-aw-island-end:workflow-a -->\nAfter";
+      const result = findIsland(body, "workflow-b");
       expect(result.found).toBe(false);
     });
 
-    it("should handle multiple islands with different run IDs", () => {
-      const body = "<!-- gh-aw-island-start:100 -->\nIsland 1\n<!-- gh-aw-island-end:100 -->\n<!-- gh-aw-island-start:200 -->\nIsland 2\n<!-- gh-aw-island-end:200 -->";
-      const result1 = findIsland(body, 100);
-      const result2 = findIsland(body, 200);
+    it("should handle multiple islands with different workflow IDs", () => {
+      const body = "<!-- gh-aw-island-start:workflow-1 -->\nIsland 1\n<!-- gh-aw-island-end:workflow-1 -->\n<!-- gh-aw-island-start:workflow-2 -->\nIsland 2\n<!-- gh-aw-island-end:workflow-2 -->";
+      const result1 = findIsland(body, "workflow-1");
+      const result2 = findIsland(body, "workflow-2");
       expect(result1.found).toBe(true);
       expect(result2.found).toBe(true);
       expect(result1.startIndex).toBeLessThan(result2.startIndex);
@@ -106,7 +106,7 @@ describe("update_pr_description_helpers.cjs", () => {
         operation: "replace",
         workflowName: "Test",
         runUrl: "https://github.com/test/actions/runs/123",
-        runId: 123,
+        workflowId: "test-workflow",
       });
       expect(result).toContain("New content");
       expect(result).not.toContain("Old content");
@@ -125,7 +125,7 @@ describe("update_pr_description_helpers.cjs", () => {
         operation: "append",
         workflowName: "Test",
         runUrl: "https://github.com/test/actions/runs/123",
-        runId: 123,
+        workflowId: "test-workflow",
       });
       expect(result).toContain("---");
       expect(result).toContain("New content");
@@ -142,7 +142,7 @@ describe("update_pr_description_helpers.cjs", () => {
         operation: "append",
         workflowName: "Test",
         runUrl: "https://github.com/test/actions/runs/123",
-        runId: 123,
+        workflowId: "test-workflow",
       });
       expect(result).toContain("Original content");
       expect(result).toContain("New content");
@@ -156,7 +156,7 @@ describe("update_pr_description_helpers.cjs", () => {
         operation: "append",
         workflowName: "Test",
         runUrl: "https://github.com/test/actions/runs/123",
-        runId: 123,
+        workflowId: "test-workflow",
       });
       expect(result).toContain("# Title");
       expect(result).toContain("**Bold**");
@@ -172,7 +172,7 @@ describe("update_pr_description_helpers.cjs", () => {
         operation: "prepend",
         workflowName: "Test",
         runUrl: "https://github.com/test/actions/runs/123",
-        runId: 123,
+        workflowId: "test-workflow",
       });
       expect(result).toContain("---");
       expect(result).toContain("New content");
@@ -189,7 +189,7 @@ describe("update_pr_description_helpers.cjs", () => {
         operation: "prepend",
         workflowName: "Test",
         runUrl: "https://github.com/test/actions/runs/123",
-        runId: 123,
+        workflowId: "test-workflow",
       });
       expect(result).toContain("Original content");
       expect(result).toContain("New content");
@@ -205,12 +205,12 @@ describe("update_pr_description_helpers.cjs", () => {
         operation: "replace-island",
         workflowName: "Test",
         runUrl: "https://github.com/test/actions/runs/123",
-        runId: 123,
+        workflowId: "test-workflow",
       });
       expect(result).toContain("Original content");
       expect(result).toContain("Island content");
-      expect(result).toContain("<!-- gh-aw-island-start:123 -->");
-      expect(result).toContain("<!-- gh-aw-island-end:123 -->");
+      expect(result).toContain("<!-- gh-aw-island-start:test-workflow -->");
+      expect(result).toContain("<!-- gh-aw-island-end:test-workflow -->");
       // Check for footer elements (uses messages system)
       expect(result).toContain("Test");
       expect(result).toContain("https://github.com/test/actions/runs/123");
@@ -218,33 +218,33 @@ describe("update_pr_description_helpers.cjs", () => {
     });
 
     it("should replace existing island content", () => {
-      const currentBody = "Before\n<!-- gh-aw-island-start:123 -->\nOld island\n<!-- gh-aw-island-end:123 -->\nAfter";
+      const currentBody = "Before\n<!-- gh-aw-island-start:test-workflow -->\nOld island\n<!-- gh-aw-island-end:test-workflow -->\nAfter";
       const result = updateBody({
         currentBody,
         newContent: "New island",
         operation: "replace-island",
         workflowName: "Test",
         runUrl: "https://github.com/test/actions/runs/123",
-        runId: 123,
+        workflowId: "test-workflow",
       });
       expect(result).toContain("Before");
       expect(result).toContain("After");
       expect(result).toContain("New island");
       expect(result).not.toContain("Old island");
-      expect(result).toContain("<!-- gh-aw-island-start:123 -->");
-      expect(result).toContain("<!-- gh-aw-island-end:123 -->");
+      expect(result).toContain("<!-- gh-aw-island-start:test-workflow -->");
+      expect(result).toContain("<!-- gh-aw-island-end:test-workflow -->");
       expect(mockCore.info).toHaveBeenCalledWith(expect.stringContaining("updating existing island"));
     });
 
     it("should preserve content outside island when replacing", () => {
-      const currentBody = "# Title\n\nSome intro\n\n<!-- gh-aw-island-start:123 -->\nOld\n<!-- gh-aw-island-end:123 -->\n\n## Footer\n\nMore content";
+      const currentBody = "# Title\n\nSome intro\n\n<!-- gh-aw-island-start:test-workflow -->\nOld\n<!-- gh-aw-island-end:test-workflow -->\n\n## Footer\n\nMore content";
       const result = updateBody({
         currentBody,
         newContent: "Updated content",
         operation: "replace-island",
         workflowName: "Test",
         runUrl: "https://github.com/test/actions/runs/123",
-        runId: 123,
+        workflowId: "test-workflow",
       });
       expect(result).toContain("# Title");
       expect(result).toContain("Some intro");
@@ -254,33 +254,33 @@ describe("update_pr_description_helpers.cjs", () => {
       expect(result).not.toContain("Old");
     });
 
-    it("should not replace island with different run ID", () => {
-      const currentBody = "Before\n<!-- gh-aw-island-start:456 -->\nOther island\n<!-- gh-aw-island-end:456 -->\nAfter";
+    it("should not replace island with different workflow ID", () => {
+      const currentBody = "Before\n<!-- gh-aw-island-start:other-workflow -->\nOther island\n<!-- gh-aw-island-end:other-workflow -->\nAfter";
       const result = updateBody({
         currentBody,
         newContent: "New island",
         operation: "replace-island",
         workflowName: "Test",
         runUrl: "https://github.com/test/actions/runs/123",
-        runId: 123,
+        workflowId: "test-workflow",
       });
-      // Should append because island 123 doesn't exist
+      // Should append because island test-workflow doesn't exist
       expect(result).toContain("Other island");
       expect(result).toContain("New island");
-      expect(result).toContain("<!-- gh-aw-island-start:456 -->");
-      expect(result).toContain("<!-- gh-aw-island-start:123 -->");
+      expect(result).toContain("<!-- gh-aw-island-start:other-workflow -->");
+      expect(result).toContain("<!-- gh-aw-island-start:test-workflow -->");
       expect(mockCore.info).toHaveBeenCalledWith(expect.stringContaining("falling back to append"));
     });
 
-    it("should handle multiple islands with same run ID (replace first)", () => {
-      const currentBody = "<!-- gh-aw-island-start:123 -->\nFirst\n<!-- gh-aw-island-end:123 -->\n<!-- gh-aw-island-start:123 -->\nSecond\n<!-- gh-aw-island-end:123 -->";
+    it("should handle multiple islands with same workflow ID (replace first)", () => {
+      const currentBody = "<!-- gh-aw-island-start:test-workflow -->\nFirst\n<!-- gh-aw-island-end:test-workflow -->\n<!-- gh-aw-island-start:test-workflow -->\nSecond\n<!-- gh-aw-island-end:test-workflow -->";
       const result = updateBody({
         currentBody,
         newContent: "Replaced",
         operation: "replace-island",
         workflowName: "Test",
         runUrl: "https://github.com/test/actions/runs/123",
-        runId: 123,
+        workflowId: "test-workflow",
       });
       expect(result).toContain("Replaced");
       // First island should be replaced
@@ -288,14 +288,14 @@ describe("update_pr_description_helpers.cjs", () => {
     });
 
     it("should handle empty island content", () => {
-      const currentBody = "Before\n<!-- gh-aw-island-start:123 -->\n\n<!-- gh-aw-island-end:123 -->\nAfter";
+      const currentBody = "Before\n<!-- gh-aw-island-start:test-workflow -->\n\n<!-- gh-aw-island-end:test-workflow -->\nAfter";
       const result = updateBody({
         currentBody,
         newContent: "New content",
         operation: "replace-island",
         workflowName: "Test",
         runUrl: "https://github.com/test/actions/runs/123",
-        runId: 123,
+        workflowId: "test-workflow",
       });
       expect(result).toContain("New content");
       expect(result).toContain("Before");
@@ -303,14 +303,14 @@ describe("update_pr_description_helpers.cjs", () => {
     });
 
     it("should handle special characters in island content", () => {
-      const currentBody = "<!-- gh-aw-island-start:123 -->\nOld\n<!-- gh-aw-island-end:123 -->";
+      const currentBody = "<!-- gh-aw-island-start:test-workflow -->\nOld\n<!-- gh-aw-island-end:test-workflow -->";
       const result = updateBody({
         currentBody,
         newContent: "Content with **markdown**, `code`, [links](http://example.com)",
         operation: "replace-island",
         workflowName: "Test",
         runUrl: "https://github.com/test/actions/runs/123",
-        runId: 123,
+        workflowId: "test-workflow",
       });
       expect(result).toContain("**markdown**");
       expect(result).toContain("`code`");
@@ -318,14 +318,14 @@ describe("update_pr_description_helpers.cjs", () => {
     });
 
     it("should handle newlines and whitespace correctly", () => {
-      const currentBody = "<!-- gh-aw-island-start:123 -->\n  \n\nOld\n\n  \n<!-- gh-aw-island-end:123 -->";
+      const currentBody = "<!-- gh-aw-island-start:test-workflow -->\n  \n\nOld\n\n  \n<!-- gh-aw-island-end:test-workflow -->";
       const result = updateBody({
         currentBody,
         newContent: "New\n\nMultiline\n\nContent",
         operation: "replace-island",
         workflowName: "Test",
         runUrl: "https://github.com/test/actions/runs/123",
-        runId: 123,
+        workflowId: "test-workflow",
       });
       expect(result).toContain("New\n\nMultiline\n\nContent");
     });
@@ -339,7 +339,7 @@ describe("update_pr_description_helpers.cjs", () => {
         operation: "append",
         workflowName: "Test",
         runUrl: "https://github.com/test/actions/runs/123",
-        runId: 123,
+        workflowId: "test-workflow",
       });
       expect(result).toContain("Original");
       // Check for footer elements
@@ -353,7 +353,7 @@ describe("update_pr_description_helpers.cjs", () => {
         operation: "append",
         workflowName: "Test",
         runUrl: "https://github.com/test/actions/runs/123",
-        runId: 123,
+        workflowId: "test-workflow",
       });
       expect(result).toContain("New");
     });
@@ -365,7 +365,7 @@ describe("update_pr_description_helpers.cjs", () => {
         operation: "append",
         workflowName: "Test",
         runUrl: "https://github.com/test/actions/runs/123",
-        runId: 123,
+        workflowId: "test-workflow",
       });
       expect(result).toContain("你好");
       expect(result).toContain("世界 🚀");
@@ -379,7 +379,7 @@ describe("update_pr_description_helpers.cjs", () => {
         operation: "append",
         workflowName: "Test",
         runUrl: "https://github.com/test/actions/runs/123",
-        runId: 123,
+        workflowId: "test-workflow",
       });
       expect(result).toContain(longContent);
       expect(result.length).toBeGreaterThan(10000);
@@ -392,7 +392,7 @@ describe("update_pr_description_helpers.cjs", () => {
         operation: "unknown",
         workflowName: "Test",
         runUrl: "https://github.com/test/actions/runs/123",
-        runId: 123,
+        workflowId: "test-workflow",
       });
       expect(result).toContain("Original");
       expect(result).toContain("New");
@@ -409,7 +409,7 @@ describe("update_pr_description_helpers.cjs", () => {
         operation: "append",
         workflowName: "Test",
         runUrl: "https://github.com/test/actions/runs/123",
-        runId: 123,
+        workflowId: "test-workflow",
         includeFooter: false,
       });
       expect(result).toContain("Original");
@@ -425,7 +425,7 @@ describe("update_pr_description_helpers.cjs", () => {
         operation: "append",
         workflowName: "Test",
         runUrl: "https://github.com/test/actions/runs/123",
-        runId: 123,
+        workflowId: "test-workflow",
         // includeFooter not specified, should default to true
       });
       expect(result).toContain("Original");
@@ -440,7 +440,7 @@ describe("update_pr_description_helpers.cjs", () => {
         operation: "append",
         workflowName: "Test",
         runUrl: "https://github.com/test/actions/runs/123",
-        runId: 123,
+        workflowId: "test-workflow",
         includeFooter: true,
       });
       expect(result).toContain("Original");
@@ -455,7 +455,7 @@ describe("update_pr_description_helpers.cjs", () => {
         operation: "replace",
         workflowName: "Test",
         runUrl: "https://github.com/test/actions/runs/123",
-        runId: 123,
+        workflowId: "test-workflow",
         includeFooter: false,
       });
       expect(result).toBe("Replacement");
@@ -469,7 +469,7 @@ describe("update_pr_description_helpers.cjs", () => {
         operation: "prepend",
         workflowName: "Test",
         runUrl: "https://github.com/test/actions/runs/123",
-        runId: 123,
+        workflowId: "test-workflow",
         includeFooter: false,
       });
       expect(result).toContain("Prepended");
@@ -478,22 +478,22 @@ describe("update_pr_description_helpers.cjs", () => {
     });
 
     it("should omit footer in replace-island operation when includeFooter is false", () => {
-      const currentBody = "Before\n<!-- gh-aw-island-start:123 -->\nOld island\n<!-- gh-aw-island-end:123 -->\nAfter";
+      const currentBody = "Before\n<!-- gh-aw-island-start:test-workflow -->\nOld island\n<!-- gh-aw-island-end:test-workflow -->\nAfter";
       const result = updateBody({
         currentBody,
         newContent: "New island",
         operation: "replace-island",
         workflowName: "Test",
         runUrl: "https://github.com/test/actions/runs/123",
-        runId: 123,
+        workflowId: "test-workflow",
         includeFooter: false,
       });
       expect(result).toContain("Before");
       expect(result).toContain("New island");
       expect(result).toContain("After");
       expect(result).not.toContain("Generated by");
-      expect(result).toContain("<!-- gh-aw-island-start:123 -->");
-      expect(result).toContain("<!-- gh-aw-island-end:123 -->");
+      expect(result).toContain("<!-- gh-aw-island-start:test-workflow -->");
+      expect(result).toContain("<!-- gh-aw-island-end:test-workflow -->");
     });
   });
 });
diff --git a/actions/setup/js/update_pull_request.cjs b/actions/setup/js/update_pull_request.cjs
index 04f825c421..3cca5ad45e 100644
--- a/actions/setup/js/update_pull_request.cjs
+++ b/actions/setup/js/update_pull_request.cjs
@@ -41,6 +41,7 @@ async function executePRUpdate(github, context, prNumber, updateData) {
 
     // Get workflow run URL for AI attribution
     const workflowName = process.env.GH_AW_WORKFLOW_NAME || "GitHub Agentic Workflow";
+    const workflowId = process.env.GH_AW_WORKFLOW_ID || "";
     const runUrl = `${context.serverUrl}/${context.repo.owner}/${context.repo.repo}/actions/runs/${context.runId}`;
 
     // Use helper to update body (handles all operations including replace)
@@ -50,7 +51,7 @@ async function executePRUpdate(github, context, prNumber, updateData) {
       operation,
       workflowName,
       runUrl,
-      runId: context.runId,
+      workflowId,
     });
 
     core.info(`Will update body (length: ${apiData.body.length})`);
diff --git a/actions/setup/js/update_release.cjs b/actions/setup/js/update_release.cjs
index 08611d3116..667974151a 100644
--- a/actions/setup/js/update_release.cjs
+++ b/actions/setup/js/update_release.cjs
@@ -83,6 +83,7 @@ async function main(config = {}) {
 
       // Get workflow run URL for AI attribution
       const runUrl = `${context.serverUrl}/${context.repo.owner}/${context.repo.repo}/actions/runs/${context.runId}`;
+      const workflowId = process.env.GH_AW_WORKFLOW_ID || "";
 
       // Use shared helper to update body based on operation
       const newBody = updateBody({
@@ -91,7 +92,7 @@ async function main(config = {}) {
         operation: message.operation || "append",
         workflowName,
         runUrl,
-        runId: context.runId,
+        workflowId,
         includeFooter, // Pass footer flag to helper
       });