diff --git a/packages/sdk/src/server/lib/pull-requests/__tests__/source-control-pull-requests.test.ts b/packages/sdk/src/server/lib/pull-requests/__tests__/source-control-pull-requests.test.ts
index a2ae1ea3c..27c0079d9 100644
--- a/packages/sdk/src/server/lib/pull-requests/__tests__/source-control-pull-requests.test.ts
+++ b/packages/sdk/src/server/lib/pull-requests/__tests__/source-control-pull-requests.test.ts
@@ -1578,6 +1578,75 @@ describe('optional targetBranch', () => {
     );
   });
 
+  it('does not duplicate entity-prefixed harness attribution when the canonical line uses a zero-width space', async () => {
+    const octokit = makeOctokit({
+      list: [],
+      created: {
+        number: 13,
+        node_id: 'node-13',
+        html_url: 'https://github.com/acme/web/pull/13',
+        title: '[Feature] X',
+        draft: true,
+        base: { ref: 'develop' },
+      },
+    });
+    const harnessAttribution =
+      '> &#8203;<!-- roomote:pr-attribution:start -->Created by Roomote.<!-- roomote:pr-attribution:end --> [View the task](https://example.com/task/1) or mention @roomote-roomote for follow-up asks.';
+    const canonicalAttribution =
+      '> \u200B<!-- roomote:pr-attribution:start -->Created by Roomote.<!-- roomote:pr-attribution:end --> Follow up by mentioning @roomote-roomote or in [the web UI](https://example.com/task/1).';
+    mockGetPrBodyAttributionLine.mockReturnValueOnce(canonicalAttribution);
+
+    await createOrUpdateSourceControlPullRequestForTaskRun({
+      taskRun: makeTaskRun({ repo: 'acme/web' }),
+      input: {
+        ...baseInput,
+        targetBranch: 'develop',
+        body: `${harnessAttribution}\n\n## What changed\n\nDone.`,
+      },
+    });
+
+    expect(octokit.rest.pulls.create).toHaveBeenCalledWith(
+      expect.objectContaining({
+        body: `${canonicalAttribution}\n\n## What changed\n\nDone.`,
+      }),
+    );
+  });
+
+  it('collapses the exact duplicated PR attribution shape to one canonical line', async () => {
+    const harnessAttribution =
+      '> &#8203;<!-- roomote:pr-attribution:start -->Created by Roomote.<!-- roomote:pr-attribution:end --> [View the task](https://example.com/task/1) or mention @roomote-roomote for follow-up asks.';
+    const staleCanonicalAttribution =
+      '> \u200B<!-- roomote:pr-attribution:start -->Created by Roomote.<!-- roomote:pr-attribution:end --> Follow up by mentioning @roomote-roomote or in [the web UI](https://example.com/task/1).';
+    const duplicatedBody = `${harnessAttribution}\n\n${staleCanonicalAttribution}\n\n## What changed\n\nDone.`;
+    const existing = {
+      number: 13,
+      node_id: 'node-13',
+      html_url: 'https://github.com/acme/web/pull/13',
+      title: '[Feature] X',
+      draft: true,
+      base: { ref: 'develop' },
+      body: duplicatedBody,
+    };
+    const octokit = makeOctokit({ list: [existing], updated: existing });
+    const canonicalAttribution = attributionBody('Created by Roomote.');
+    mockGetPrBodyAttributionLine.mockReturnValueOnce(canonicalAttribution);
+
+    await createOrUpdateSourceControlPullRequestForTaskRun({
+      taskRun: makeTaskRun({ repo: 'acme/web' }),
+      input: {
+        ...baseInput,
+        targetBranch: 'develop',
+        body: duplicatedBody,
+      },
+    });
+
+    expect(octokit.rest.pulls.update).toHaveBeenCalledWith(
+      expect.objectContaining({
+        body: `${canonicalAttribution}\n\n## What changed\n\nDone.`,
+      }),
+    );
+  });
+
   it('preserves the opener attribution when updating a private pull request', async () => {
     const existing = {
       number: 11,
diff --git a/packages/sdk/src/server/lib/pull-requests/source-control-pull-requests.ts b/packages/sdk/src/server/lib/pull-requests/source-control-pull-requests.ts
index 325f8aedb..b98d5baad 100644
--- a/packages/sdk/src/server/lib/pull-requests/source-control-pull-requests.ts
+++ b/packages/sdk/src/server/lib/pull-requests/source-control-pull-requests.ts
@@ -25,7 +25,7 @@ import {
 import {
   buildPullRequestUrl,
   getSourceControlProviderLabel,
-  findPrBodyAttributionLine,
+  findPrBodyAttributionMarkers,
   preservePrBodyAttribution,
   getCommunicationProviderFromTaskPayload,
   getCommunicationGuildIdFromTaskPayload,
@@ -666,22 +666,31 @@ function buildPrAttributionTaskUrl(taskRun: TaskRun): string {
 }
 
 function prependCanonicalPrAttribution(body: string, line: string): string {
-  const firstLineEnd = body.indexOf('\n');
-  const firstLine = body.slice(
+  let remainingBody = body.trimStart();
+
+  while (remainingBody) {
+    const markers = findPrBodyAttributionMarkers(remainingBody);
+    if (!markers || remainingBody.slice(0, markers.lineStart).trim()) {
+      break;
+    }
+
+    remainingBody = remainingBody.slice(markers.lineEnd).trimStart();
+  }
+
+  const firstLineEnd = remainingBody.indexOf('\n');
+  const firstLine = remainingBody.slice(
     0,
-    firstLineEnd === -1 ? body.length : firstLineEnd,
+    firstLineEnd === -1 ? remainingBody.length : firstLineEnd,
   );
-  const normalizedFirstLine = firstLine.trimStart();
-  const hasLeadingAttribution =
-    findPrBodyAttributionLine(firstLine) !== null ||
+  if (
     /^> (?:Opened on behalf of .+\.|Created by Roomote\.) (?:Follow up by mentioning @|\[View the task\]\().+$/u.test(
-      normalizedFirstLine,
-    );
-  const remainingBody = hasLeadingAttribution
-    ? body
-        .slice(firstLineEnd === -1 ? body.length : firstLineEnd + 1)
-        .trimStart()
-    : body.trimStart();
+      firstLine.trimStart(),
+    )
+  ) {
+    remainingBody = remainingBody
+      .slice(firstLineEnd === -1 ? remainingBody.length : firstLineEnd + 1)
+      .trimStart();
+  }
 
   return remainingBody ? `${line}\n\n${remainingBody}` : line;
 }
diff --git a/packages/types/src/__tests__/github-bot-identity.test.ts b/packages/types/src/__tests__/github-bot-identity.test.ts
index 0475d8c26..ba8b6ae7a 100644
--- a/packages/types/src/__tests__/github-bot-identity.test.ts
+++ b/packages/types/src/__tests__/github-bot-identity.test.ts
@@ -1,4 +1,5 @@
 import {
+  findPrBodyAttributionLine,
   formatPrBodyAttribution,
   matchesRoomoteGitHubLogin,
   normalizePrBodyAttributionAppMention,
@@ -17,6 +18,15 @@ describe('Roomote GitHub bot identity helpers', () => {
         '> &#8203;<!-- roomote:pr-attribution:start -->Opened on behalf of @octocat.<!-- roomote:pr-attribution:end --> Follow up in [the web UI](https://example.com/task/1).',
       );
     });
+
+    it.each(['&#8203;', '&amp;#8203;', '\u200B'])(
+      'finds marker-wrapped attribution with the %s prefix',
+      (prefix) => {
+        const body = `\n\n> ${prefix}<!-- roomote:pr-attribution:start -->Created by Roomote.<!-- roomote:pr-attribution:end --> Follow up by mentioning @roomote.`;
+
+        expect(findPrBodyAttributionLine(body)).toBe('> Created by Roomote.');
+      },
+    );
   });
 
   describe('matchesRoomoteGitHubLogin', () => {
diff --git a/packages/types/src/constants.ts b/packages/types/src/constants.ts
index 6848e6232..53cadafb7 100644
--- a/packages/types/src/constants.ts
+++ b/packages/types/src/constants.ts
@@ -91,14 +91,14 @@ export const PR_BODY_ATTRIBUTION_END_MARKER =
   '<!-- roomote:pr-attribution:end -->';
 const PR_BODY_ATTRIBUTION_INLINE_PREFIX = '&#8203;';
 
-type PrBodyAttributionMarkerMatch = {
+export type PrBodyAttributionMarkerMatch = {
   start: number;
   end: number;
   lineStart: number;
   lineEnd: number;
 };
 
-function findPrBodyAttributionMarkers(
+export function findPrBodyAttributionMarkers(
   body: string,
 ): PrBodyAttributionMarkerMatch | null {
   const startMarker = body.indexOf(PR_BODY_ATTRIBUTION_START_MARKER);
@@ -114,7 +114,9 @@ function findPrBodyAttributionMarkers(
 
   const lineStart = body.lastIndexOf('\n', startMarker - 1) + 1;
   if (
-    !/^[ \t]*>[ \t]*(?:&#8203;)?$/u.test(body.slice(lineStart, startMarker))
+    !/^[ \t]*>[ \t]*(?:(?:&(?:amp;)?#8203;)|\u200B)?$/u.test(
+      body.slice(lineStart, startMarker),
+    )
   ) {
     return null;
   }