diff --git a/actions/setup/js/add_comment.cjs b/actions/setup/js/add_comment.cjs
index 4e2a0f6ca21..a5d6cfef068 100644
--- a/actions/setup/js/add_comment.cjs
+++ b/actions/setup/js/add_comment.cjs
@@ -499,10 +499,88 @@ async function main(config = {}) {
     } catch (error) {
       const errorMessage = getErrorMessage(error);
 
-      // Check if this is a 404 error (discussion/issue was deleted)
+      // Check if this is a 404 error (discussion/issue was deleted or wrong type)
       // @ts-expect-error - Error handling with optional chaining
       const is404 = error?.status === 404 || errorMessage.includes("404") || errorMessage.toLowerCase().includes("not found");
 
+      // If 404 and item_number was explicitly provided and we tried as issue/PR,
+      // retry as a discussion (the user may have provided a discussion number)
+      if (is404 && !isDiscussion && item.item_number !== undefined && item.item_number !== null) {
+        core.info(`Item #${itemNumber} not found as issue/PR, retrying as discussion...`);
+
+        try {
+          // Try to find and comment on the discussion
+          const discussionQuery = `
+            query($owner: String!, $repo: String!, $number: Int!) {
+              repository(owner: $owner, name: $repo) {
+                discussion(number: $number) {
+                  id
+                }
+              }
+            }
+          `;
+          const queryResult = await github.graphql(discussionQuery, {
+            owner: repoParts.owner,
+            repo: repoParts.repo,
+            number: itemNumber,
+          });
+
+          const discussionId = queryResult?.repository?.discussion?.id;
+          if (!discussionId) {
+            throw new Error(`Discussion #${itemNumber} not found in ${itemRepo}`);
+          }
+
+          core.info(`Found discussion #${itemNumber}, adding comment...`);
+          const comment = await commentOnDiscussion(github, repoParts.owner, repoParts.repo, itemNumber, processedBody, null);
+
+          core.info(`Created comment on discussion: ${comment.html_url}`);
+
+          // Add tracking metadata
+          const commentResult = {
+            id: comment.id,
+            html_url: comment.html_url,
+            _tracking: {
+              commentId: comment.id,
+              itemNumber: itemNumber,
+              repo: itemRepo,
+              isDiscussion: true,
+            },
+          };
+
+          createdComments.push(commentResult);
+
+          return {
+            success: true,
+            commentId: comment.id,
+            url: comment.html_url,
+            itemNumber: itemNumber,
+            repo: itemRepo,
+            isDiscussion: true,
+          };
+        } catch (discussionError) {
+          const discussionErrorMessage = getErrorMessage(discussionError);
+          // @ts-expect-error - Error handling with optional chaining
+          const isDiscussion404 = discussionError?.status === 404 || discussionErrorMessage.toLowerCase().includes("not found");
+
+          if (isDiscussion404) {
+            // Neither issue/PR nor discussion found - truly doesn't exist
+            core.warning(`Target #${itemNumber} was not found as issue, PR, or discussion (may have been deleted): ${discussionErrorMessage}`);
+            return {
+              success: true,
+              warning: `Target not found: ${discussionErrorMessage}`,
+              skipped: true,
+            };
+          }
+
+          // Other error when trying as discussion
+          core.error(`Failed to add comment to discussion: ${discussionErrorMessage}`);
+          return {
+            success: false,
+            error: discussionErrorMessage,
+          };
+        }
+      }
+
       if (is404) {
         // Treat 404s as warnings - the target was deleted between execution and safe output processing
         core.warning(`Target was not found (may have been deleted): ${errorMessage}`);
diff --git a/actions/setup/js/add_comment.test.cjs b/actions/setup/js/add_comment.test.cjs
index d2bc6ea73a2..71936283a39 100644
--- a/actions/setup/js/add_comment.test.cjs
+++ b/actions/setup/js/add_comment.test.cjs
@@ -745,4 +745,211 @@ describe("add_comment", () => {
       expect(errorCalls.length).toBeGreaterThan(0);
     });
   });
+
+  describe("discussion fallback", () => {
+    it("should retry as discussion when item_number returns 404 as issue/PR", async () => {
+      const addCommentScript = fs.readFileSync(path.join(__dirname, "add_comment.cjs"), "utf8");
+
+      let infoCalls = [];
+      mockCore.info = msg => {
+        infoCalls.push(msg);
+      };
+
+      // Mock REST API to return 404 (not found as issue/PR)
+      mockGithub.rest.issues.createComment = async () => {
+        const error = new Error("Not Found");
+        // @ts-ignore
+        error.status = 404;
+        throw error;
+      };
+
+      // Mock GraphQL to return discussion
+      let graphqlCalls = [];
+      mockGithub.graphql = async (query, vars) => {
+        graphqlCalls.push({ query, vars });
+
+        // First call is to check if discussion exists
+        if (query.includes("query") && query.includes("discussion(number:")) {
+          return {
+            repository: {
+              discussion: {
+                id: "D_kwDOTest789",
+                url: "https://github.com/owner/repo/discussions/14117",
+              },
+            },
+          };
+        }
+
+        // Second call is to add comment
+        if (query.includes("mutation") && query.includes("addDiscussionComment")) {
+          return {
+            addDiscussionComment: {
+              comment: {
+                id: "DC_kwDOTest999",
+                body: "Test comment",
+                createdAt: "2026-02-06T12:00:00Z",
+                url: "https://github.com/owner/repo/discussions/14117#discussioncomment-999",
+              },
+            },
+          };
+        }
+      };
+
+      const handler = await eval(`(async () => { ${addCommentScript}; return await main({ target: 'triggering' }); })()`);
+
+      const message = {
+        type: "add_comment",
+        item_number: 14117,
+        body: "Test comment on discussion",
+      };
+
+      const result = await handler(message, {});
+
+      expect(result.success).toBe(true);
+      expect(result.isDiscussion).toBe(true);
+      expect(result.itemNumber).toBe(14117);
+      expect(result.url).toContain("discussions/14117");
+
+      // Verify it logged the retry
+      const retryLog = infoCalls.find(msg => msg.includes("retrying as discussion"));
+      expect(retryLog).toBeTruthy();
+
+      const foundLog = infoCalls.find(msg => msg.includes("Found discussion"));
+      expect(foundLog).toBeTruthy();
+    });
+
+    it("should return skipped when item_number not found as issue/PR or discussion", async () => {
+      const addCommentScript = fs.readFileSync(path.join(__dirname, "add_comment.cjs"), "utf8");
+
+      let warningCalls = [];
+      mockCore.warning = msg => {
+        warningCalls.push(msg);
+      };
+
+      // Mock REST API to return 404
+      mockGithub.rest.issues.createComment = async () => {
+        const error = new Error("Not Found");
+        // @ts-ignore
+        error.status = 404;
+        throw error;
+      };
+
+      // Mock GraphQL to also return 404 (discussion doesn't exist either)
+      mockGithub.graphql = async (query, vars) => {
+        if (query.includes("query") && query.includes("discussion(number:")) {
+          return {
+            repository: {
+              discussion: null,
+            },
+          };
+        }
+      };
+
+      const handler = await eval(`(async () => { ${addCommentScript}; return await main({ target: 'triggering' }); })()`);
+
+      const message = {
+        type: "add_comment",
+        item_number: 99999,
+        body: "Test comment",
+      };
+
+      const result = await handler(message, {});
+
+      expect(result.success).toBe(true);
+      expect(result.skipped).toBe(true);
+      expect(result.warning).toContain("not found");
+
+      // Verify warning was logged
+      const notFoundWarning = warningCalls.find(msg => msg.includes("not found"));
+      expect(notFoundWarning).toBeTruthy();
+    });
+
+    it("should not retry as discussion when 404 occurs without explicit item_number", async () => {
+      const addCommentScript = fs.readFileSync(path.join(__dirname, "add_comment.cjs"), "utf8");
+
+      let warningCalls = [];
+      mockCore.warning = msg => {
+        warningCalls.push(msg);
+      };
+
+      // Mock REST API to return 404
+      mockGithub.rest.issues.createComment = async () => {
+        const error = new Error("Not Found");
+        // @ts-ignore
+        error.status = 404;
+        throw error;
+      };
+
+      // GraphQL should not be called
+      let graphqlCalled = false;
+      mockGithub.graphql = async () => {
+        graphqlCalled = true;
+        throw new Error("GraphQL should not be called");
+      };
+
+      const handler = await eval(`(async () => { ${addCommentScript}; return await main({ target: 'triggering' }); })()`);
+
+      const message = {
+        type: "add_comment",
+        // No item_number - using target resolution
+        body: "Test comment",
+      };
+
+      const result = await handler(message, {});
+
+      expect(result.success).toBe(true);
+      expect(result.skipped).toBe(true);
+      expect(graphqlCalled).toBe(false);
+
+      // Verify warning was logged
+      const notFoundWarning = warningCalls.find(msg => msg.includes("not found"));
+      expect(notFoundWarning).toBeTruthy();
+    });
+
+    it("should not retry as discussion when already detected as discussion context", async () => {
+      const addCommentScript = fs.readFileSync(path.join(__dirname, "add_comment.cjs"), "utf8");
+
+      // Set discussion context
+      mockContext.eventName = "discussion";
+      mockContext.payload = {
+        discussion: {
+          number: 100,
+        },
+      };
+
+      let warningCalls = [];
+      mockCore.warning = msg => {
+        warningCalls.push(msg);
+      };
+
+      // Mock GraphQL to return 404 for discussion
+      let graphqlCallCount = 0;
+      mockGithub.graphql = async (query, vars) => {
+        graphqlCallCount++;
+
+        if (query.includes("query") && query.includes("discussion(number:")) {
+          return {
+            repository: {
+              discussion: null,
+            },
+          };
+        }
+      };
+
+      const handler = await eval(`(async () => { ${addCommentScript}; return await main({ target: 'triggering' }); })()`);
+
+      const message = {
+        type: "add_comment",
+        body: "Test comment",
+      };
+
+      const result = await handler(message, {});
+
+      expect(result.success).toBe(true);
+      expect(result.skipped).toBe(true);
+
+      // Should only call GraphQL once (not retry)
+      expect(graphqlCallCount).toBe(1);
+    });
+  });
 });