diff --git a/.changeset/patch-add-safe-output-summaries.md b/.changeset/patch-add-safe-output-summaries.md
new file mode 100644
index 00000000000..52f2922e47d
--- /dev/null
+++ b/.changeset/patch-add-safe-output-summaries.md
@@ -0,0 +1,12 @@
+---
+"gh-aw": patch
+---
+
+Add step summaries for safe-output processing results.
+
+Safe-output handlers now generate collapsible step summaries for each processed
+message, providing visibility into what was created or updated during workflow
+execution. Body previews are truncated at 500 characters to avoid bloat. The
+feature is implemented for both regular safe-outputs and project-based
+safe-outputs via a shared helper module.
+
diff --git a/actions/setup/js/safe_output_handler_manager.cjs b/actions/setup/js/safe_output_handler_manager.cjs
index a58b1c87a1a..5838c4e241a 100644
--- a/actions/setup/js/safe_output_handler_manager.cjs
+++ b/actions/setup/js/safe_output_handler_manager.cjs
@@ -14,6 +14,7 @@ const { getErrorMessage } = require("./error_helpers.cjs");
 const { hasUnresolvedTemporaryIds, replaceTemporaryIdReferences, normalizeTemporaryId } = require("./temporary_id.cjs");
 const { generateMissingInfoSections } = require("./missing_info_formatter.cjs");
 const { setCollectedMissings } = require("./missing_messages_helper.cjs");
+const { writeSafeOutputSummaries } = require("./safe_output_summary.cjs");
 
 const DEFAULT_AGENTIC_CAMPAIGN_LABEL = "agentic-campaign";
 
@@ -835,6 +836,9 @@ async function main() {
       syntheticUpdateCount = await processSyntheticUpdates(github, context, processingResult.outputsWithUnresolvedIds, temporaryIdMap);
     }
 
+    // Write step summaries for all processed safe-outputs
+    await writeSafeOutputSummaries(processingResult.results, agentOutput.items);
+
     // Log summary
     const successCount = processingResult.results.filter(r => r.success).length;
     const failureCount = processingResult.results.filter(r => !r.success && !r.deferred && !r.skipped).length;
diff --git a/actions/setup/js/safe_output_project_handler_manager.cjs b/actions/setup/js/safe_output_project_handler_manager.cjs
index d4b69d7b5ba..3f9bbe477ab 100644
--- a/actions/setup/js/safe_output_project_handler_manager.cjs
+++ b/actions/setup/js/safe_output_project_handler_manager.cjs
@@ -15,6 +15,7 @@
 
 const { loadAgentOutput } = require("./load_agent_output.cjs");
 const { getErrorMessage } = require("./error_helpers.cjs");
+const { writeSafeOutputSummaries } = require("./safe_output_summary.cjs");
 
 /**
  * Handler map configuration for project-related safe outputs
@@ -226,6 +227,9 @@ async function main() {
     // Process messages
     const { results, processedCount, temporaryProjectMap } = await processMessages(messageHandlers, messages);
 
+    // Write step summaries for all processed safe-outputs
+    await writeSafeOutputSummaries(results, messages);
+
     // Set outputs
     core.setOutput("processed_count", processedCount);
 
diff --git a/actions/setup/js/safe_output_summary.cjs b/actions/setup/js/safe_output_summary.cjs
new file mode 100644
index 00000000000..a110f8c45aa
--- /dev/null
+++ b/actions/setup/js/safe_output_summary.cjs
@@ -0,0 +1,131 @@
+// @ts-check
+/// <reference types="@actions/github-script" />
+
+/**
+ * Safe Output Summary Generator
+ *
+ * This module provides functionality to generate step summaries for safe-output messages.
+ * Each processed safe-output generates a summary enclosed in a <details> section.
+ */
+
+/**
+ * Generate a step summary for a single safe-output message
+ * @param {Object} options - Summary generation options
+ * @param {string} options.type - The safe-output type (e.g., "create_issue", "create_project")
+ * @param {number} options.messageIndex - The message index (1-based)
+ * @param {boolean} options.success - Whether the message was processed successfully
+ * @param {any} options.result - The result from the handler
+ * @param {any} options.message - The original message
+ * @param {string} [options.error] - Error message if processing failed
+ * @returns {string} - Markdown content for the step summary
+ */
+function generateSafeOutputSummary(options) {
+  const { type, messageIndex, success, result, message, error } = options;
+
+  // Format the type for display (e.g., "create_issue" -> "Create Issue")
+  const displayType = type
+    .split("_")
+    .map(word => word.charAt(0).toUpperCase() + word.slice(1))
+    .join(" ");
+
+  // Choose emoji and status based on success
+  const emoji = success ? "✅" : "❌";
+  const status = success ? "Success" : "Failed";
+
+  // Start building the summary
+  let summary = `<details>\n<summary>${emoji} ${displayType} - ${status} (Message ${messageIndex})</summary>\n\n`;
+
+  // Add message details
+  summary += `### ${displayType}\n\n`;
+
+  if (success && result) {
+    // Add result-specific information based on type
+    if (result.url) {
+      summary += `**URL:** ${result.url}\n\n`;
+    }
+    if (result.repo && result.number) {
+      summary += `**Location:** ${result.repo}#${result.number}\n\n`;
+    }
+    if (result.projectUrl) {
+      summary += `**Project URL:** ${result.projectUrl}\n\n`;
+    }
+    if (result.temporaryId) {
+      summary += `**Temporary ID:** \`${result.temporaryId}\`\n\n`;
+    }
+
+    // Add original message details if available
+    if (message) {
+      if (message.title) {
+        summary += `**Title:** ${message.title}\n\n`;
+      }
+      if (message.body && typeof message.body === "string") {
+        // Truncate body if too long
+        const maxBodyLength = 500;
+        const bodyPreview = message.body.length > maxBodyLength ? message.body.substring(0, maxBodyLength) + "..." : message.body;
+        summary += `**Body Preview:**\n\`\`\`\n${bodyPreview}\n\`\`\`\n\n`;
+      }
+      if (message.labels && Array.isArray(message.labels)) {
+        summary += `**Labels:** ${message.labels.join(", ")}\n\n`;
+      }
+    }
+  } else if (error) {
+    // Show error information
+    summary += `**Error:** ${error}\n\n`;
+
+    // Add original message details for debugging
+    if (message) {
+      summary += `**Message Details:**\n\`\`\`json\n${JSON.stringify(message, null, 2).substring(0, 1000)}\n\`\`\`\n\n`;
+    }
+  }
+
+  summary += `</details>\n\n`;
+
+  return summary;
+}
+
+/**
+ * Write safe-output summaries to the GitHub Actions step summary
+ * @param {Array<Object>} results - Array of processing results
+ * @param {Array<Object>} messages - Array of original messages
+ * @returns {Promise<void>}
+ */
+async function writeSafeOutputSummaries(results, messages) {
+  if (!results || results.length === 0) {
+    return;
+  }
+
+  let summaryContent = `## Safe Output Processing Summary\n\n`;
+  summaryContent += `Processed ${results.length} safe-output message(s).\n\n`;
+
+  // Generate summary for each result
+  for (const result of results) {
+    // Skip if this was handled by a standalone step
+    if (result.skipped) {
+      continue;
+    }
+
+    // Get the original message
+    const message = messages[result.messageIndex];
+
+    summaryContent += generateSafeOutputSummary({
+      type: result.type,
+      messageIndex: result.messageIndex + 1, // Convert to 1-based
+      success: result.success,
+      result: result.result,
+      message: message,
+      error: result.error,
+    });
+  }
+
+  try {
+    await core.summary.addRaw(summaryContent).write();
+    core.info(`📝 Safe output summaries written to step summary`);
+  } catch (error) {
+    core.warning(`Failed to write safe output summaries: ${error instanceof Error ? error.message : String(error)}`);
+  }
+}
+
+module.exports = {
+  generateSafeOutputSummary,
+  writeSafeOutputSummaries,
+};
diff --git a/actions/setup/js/safe_output_summary.test.cjs b/actions/setup/js/safe_output_summary.test.cjs
new file mode 100644
index 00000000000..fc37175b9d2
--- /dev/null
+++ b/actions/setup/js/safe_output_summary.test.cjs
@@ -0,0 +1,211 @@
+import { describe, it, expect, beforeEach, vi } from "vitest";
+
+// Mock the global objects that GitHub Actions provides
+const mockCore = {
+  info: vi.fn(),
+  warning: vi.fn(),
+  summary: {
+    addRaw: vi.fn().mockReturnThis(),
+    write: vi.fn().mockResolvedValue(undefined),
+  },
+};
+
+// Set up global mocks before importing the module
+globalThis.core = mockCore;
+
+const { generateSafeOutputSummary, writeSafeOutputSummaries } = await import("./safe_output_summary.cjs");
+
+describe("safe_output_summary", () => {
+  beforeEach(() => {
+    vi.clearAllMocks();
+  });
+
+  describe("generateSafeOutputSummary", () => {
+    it("should generate summary for successful create_issue", () => {
+      const options = {
+        type: "create_issue",
+        messageIndex: 1,
+        success: true,
+        result: {
+          repo: "owner/repo",
+          number: 123,
+          url: "https://github.com/owner/repo/issues/123",
+          temporaryId: "issue-1",
+        },
+        message: {
+          title: "Test Issue",
+          body: "This is a test issue body",
+          labels: ["bug", "enhancement"],
+        },
+      };
+
+      const summary = generateSafeOutputSummary(options);
+
+      expect(summary).toContain("<details>");
+      expect(summary).toContain("</details>");
+      expect(summary).toContain("✅");
+      expect(summary).toContain("Create Issue");
+      expect(summary).toContain("Message 1");
+      expect(summary).toContain("owner/repo#123");
+      expect(summary).toContain("https://github.com/owner/repo/issues/123");
+      expect(summary).toContain("issue-1");
+      expect(summary).toContain("Test Issue");
+      expect(summary).toContain("bug, enhancement");
+    });
+
+    it("should generate summary for failed message with error", () => {
+      const options = {
+        type: "create_project",
+        messageIndex: 2,
+        success: false,
+        result: null,
+        message: {
+          title: "Test Project",
+        },
+        error: "Failed to create project: permission denied",
+      };
+
+      const summary = generateSafeOutputSummary(options);
+
+      expect(summary).toContain("❌");
+      expect(summary).toContain("Failed");
+      expect(summary).toContain("Create Project");
+      expect(summary).toContain("Message 2");
+      expect(summary).toContain("permission denied");
+    });
+
+    it("should truncate long body content", () => {
+      const longBody = "a".repeat(1000);
+
+      const options = {
+        type: "create_discussion",
+        messageIndex: 3,
+        success: true,
+        result: {
+          repo: "owner/repo",
+          number: 456,
+        },
+        message: {
+          title: "Test Discussion",
+          body: longBody,
+        },
+      };
+
+      const summary = generateSafeOutputSummary(options);
+
+      expect(summary).toContain("Body Preview");
+      expect(summary).toContain("...");
+      expect(summary.length).toBeLessThan(longBody.length + 1000);
+    });
+
+    it("should handle project-specific results", () => {
+      const options = {
+        type: "create_project",
+        messageIndex: 4,
+        success: true,
+        result: {
+          projectUrl: "https://github.com/orgs/owner/projects/123",
+        },
+        message: {
+          title: "Test Project",
+        },
+      };
+
+      const summary = generateSafeOutputSummary(options);
+
+      expect(summary).toContain("Project URL");
+      expect(summary).toContain("https://github.com/orgs/owner/projects/123");
+    });
+  });
+
+  describe("writeSafeOutputSummaries", () => {
+    it("should write summaries for multiple results", async () => {
+      const results = [
+        {
+          type: "create_issue",
+          messageIndex: 0,
+          success: true,
+          result: {
+            repo: "owner/repo",
+            number: 123,
+            url: "https://github.com/owner/repo/issues/123",
+          },
+        },
+        {
+          type: "create_project",
+          messageIndex: 1,
+          success: true,
+          result: {
+            projectUrl: "https://github.com/orgs/owner/projects/456",
+          },
+        },
+      ];
+
+      const messages = [{ title: "Issue 1", body: "Body 1" }, { title: "Project 1" }];
+
+      await writeSafeOutputSummaries(results, messages);
+
+      expect(mockCore.summary.addRaw).toHaveBeenCalledTimes(1);
+      expect(mockCore.summary.write).toHaveBeenCalledTimes(1);
+      expect(mockCore.info).toHaveBeenCalledWith("📝 Safe output summaries written to step summary");
+
+      const summaryContent = mockCore.summary.addRaw.mock.calls[0][0];
+      expect(summaryContent).toContain("Safe Output Processing Summary");
+      expect(summaryContent).toContain("Processed 2 safe-output message(s)");
+      expect(summaryContent).toContain("Create Issue");
+      expect(summaryContent).toContain("Create Project");
+    });
+
+    it("should skip results handled by standalone steps", async () => {
+      const results = [
+        {
+          type: "create_issue",
+          messageIndex: 0,
+          success: true,
+          result: { repo: "owner/repo", number: 123 },
+        },
+        {
+          type: "noop",
+          messageIndex: 1,
+          success: false,
+          skipped: true,
+          reason: "Handled by standalone step",
+        },
+      ];
+
+      const messages = [{ title: "Issue 1" }, { message: "Noop message" }];
+
+      await writeSafeOutputSummaries(results, messages);
+
+      const summaryContent = mockCore.summary.addRaw.mock.calls[0][0];
+      expect(summaryContent).toContain("Create Issue");
+      expect(summaryContent).not.toContain("Noop");
+    });
+
+    it("should handle empty results", async () => {
+      await writeSafeOutputSummaries([], []);
+
+      expect(mockCore.summary.addRaw).not.toHaveBeenCalled();
+      expect(mockCore.summary.write).not.toHaveBeenCalled();
+    });
+
+    it("should handle write failures gracefully", async () => {
+      mockCore.summary.write.mockRejectedValueOnce(new Error("Write failed"));
+
+      const results = [
+        {
+          type: "create_issue",
+          messageIndex: 0,
+          success: true,
+          result: { repo: "owner/repo", number: 123 },
+        },
+      ];
+
+      const messages = [{ title: "Issue 1" }];
+
+      await writeSafeOutputSummaries(results, messages);
+
+      expect(mockCore.warning).toHaveBeenCalledWith("Failed to write safe output summaries: Write failed");
+    });
+  });
+});