diff --git a/action.yml b/action.yml
index 4e148e4..dfd64c9 100644
--- a/action.yml
+++ b/action.yml
@@ -147,6 +147,8 @@ runs:
         CLAUDE_SUCCESS: ${{ steps.claude-code.outputs.conclusion == 'success' }}
         OUTPUT_FILE: ${{ steps.claude-code.outputs.execution_file || '' }}
         TRIGGER_USERNAME: ${{ github.event.comment.user.login || github.event.issue.user.login || github.event.pull_request.user.login || github.event.sender.login || github.triggering_actor || github.actor || '' }}
+        PREPARE_SUCCESS: ${{ steps.prepare.outcome == 'success' }}
+        PREPARE_ERROR: ${{ steps.prepare.outputs.prepare_error || '' }}
 
     - name: Display Claude Code Report
       if: steps.prepare.outputs.contains_trigger == 'true' && steps.claude-code.outputs.execution_file != ''
diff --git a/src/entrypoints/prepare.ts b/src/entrypoints/prepare.ts
index 1cce680..1470798 100644
--- a/src/entrypoints/prepare.ts
+++ b/src/entrypoints/prepare.ts
@@ -92,7 +92,10 @@ async function run() {
     );
     core.setOutput("mcp_config", mcpConfig);
   } catch (error) {
-    core.setFailed(`Prepare step failed with error: ${error}`);
+    const errorMessage = error instanceof Error ? error.message : String(error);
+    core.setFailed(`Prepare step failed with error: ${errorMessage}`);
+    // Also output the clean error message for the action to capture
+    core.setOutput("prepare_error", errorMessage);
     process.exit(1);
   }
 }
diff --git a/src/entrypoints/update-comment-link.ts b/src/entrypoints/update-comment-link.ts
index daa2cec..d74bcd5 100644
--- a/src/entrypoints/update-comment-link.ts
+++ b/src/entrypoints/update-comment-link.ts
@@ -145,38 +145,48 @@ async function run() {
       duration_api_ms?: number;
     } | null = null;
     let actionFailed = false;
+    let errorDetails: string | undefined;
 
-    // Check for existence of output file and parse it if available
-    try {
-      const outputFile = process.env.OUTPUT_FILE;
-      if (outputFile) {
-        const fileContent = await fs.readFile(outputFile, "utf8");
-        const outputData = JSON.parse(fileContent);
+    // First check if prepare step failed
+    const prepareSuccess = process.env.PREPARE_SUCCESS !== "false";
+    const prepareError = process.env.PREPARE_ERROR;
 
-        // Output file is an array, get the last element which contains execution details
-        if (Array.isArray(outputData) && outputData.length > 0) {
-          const lastElement = outputData[outputData.length - 1];
-          if (
-            lastElement.role === "system" &&
-            "cost_usd" in lastElement &&
-            "duration_ms" in lastElement
-          ) {
-            executionDetails = {
-              cost_usd: lastElement.cost_usd,
-              duration_ms: lastElement.duration_ms,
-              duration_api_ms: lastElement.duration_api_ms,
-            };
+    if (!prepareSuccess && prepareError) {
+      actionFailed = true;
+      errorDetails = prepareError;
+    } else {
+      // Check for existence of output file and parse it if available
+      try {
+        const outputFile = process.env.OUTPUT_FILE;
+        if (outputFile) {
+          const fileContent = await fs.readFile(outputFile, "utf8");
+          const outputData = JSON.parse(fileContent);
+
+          // Output file is an array, get the last element which contains execution details
+          if (Array.isArray(outputData) && outputData.length > 0) {
+            const lastElement = outputData[outputData.length - 1];
+            if (
+              lastElement.role === "system" &&
+              "cost_usd" in lastElement &&
+              "duration_ms" in lastElement
+            ) {
+              executionDetails = {
+                cost_usd: lastElement.cost_usd,
+                duration_ms: lastElement.duration_ms,
+                duration_api_ms: lastElement.duration_api_ms,
+              };
+            }
           }
         }
-      }
 
-      // Check if the action failed by looking at the exit code or error marker
-      const claudeSuccess = process.env.CLAUDE_SUCCESS !== "false";
-      actionFailed = !claudeSuccess;
-    } catch (error) {
-      console.error("Error reading output file:", error);
-      // If we can't read the file, check for any failure markers
-      actionFailed = process.env.CLAUDE_SUCCESS === "false";
+        // Check if the Claude action failed
+        const claudeSuccess = process.env.CLAUDE_SUCCESS !== "false";
+        actionFailed = !claudeSuccess;
+      } catch (error) {
+        console.error("Error reading output file:", error);
+        // If we can't read the file, check for any failure markers
+        actionFailed = process.env.CLAUDE_SUCCESS === "false";
+      }
     }
 
     // Prepare input for updateCommentBody function
@@ -189,6 +199,7 @@ async function run() {
       prLink,
       branchName: shouldDeleteBranch ? undefined : claudeBranch,
       triggerUsername,
+      errorDetails,
     };
 
     const updatedBody = updateCommentBody(commentInput);
diff --git a/src/github/operations/comment-logic.ts b/src/github/operations/comment-logic.ts
index 6c2bad4..6a4551a 100644
--- a/src/github/operations/comment-logic.ts
+++ b/src/github/operations/comment-logic.ts
@@ -15,6 +15,7 @@ export type CommentUpdateInput = {
   prLink?: string;
   branchName?: string;
   triggerUsername?: string;
+  errorDetails?: string;
 };
 
 export function ensureProperlyEncodedUrl(url: string): string | null {
@@ -75,6 +76,7 @@ export function updateCommentBody(input: CommentUpdateInput): string {
     actionFailed,
     branchName,
     triggerUsername,
+    errorDetails,
   } = input;
 
   // Extract content from the original comment body
@@ -177,7 +179,14 @@ export function updateCommentBody(input: CommentUpdateInput): string {
   }
 
   // Build the new body with blank line between header and separator
-  let newBody = `${header}${links}\n\n---\n`;
+  let newBody = `${header}${links}`;
+
+  // Add error details if available
+  if (actionFailed && errorDetails) {
+    newBody += `\n\n\`\`\`\n${errorDetails}\n\`\`\``;
+  }
+
+  newBody += `\n\n---\n`;
 
   // Clean up the body content
   // Remove any existing View job run, branch links from the bottom
diff --git a/test/comment-logic.test.ts b/test/comment-logic.test.ts
index 3b86908..82fec08 100644
--- a/test/comment-logic.test.ts
+++ b/test/comment-logic.test.ts
@@ -39,6 +39,25 @@ describe("updateCommentBody", () => {
       expect(result).toContain("**Claude encountered an error after 45s**");
     });
 
+    it("includes error details when provided", () => {
+      const input = {
+        ...baseInput,
+        currentBody: "Claude Code is working...",
+        actionFailed: true,
+        executionDetails: { duration_ms: 45000 },
+        errorDetails: "Failed to fetch issue data",
+      };
+
+      const result = updateCommentBody(input);
+      expect(result).toContain("**Claude encountered an error after 45s**");
+      expect(result).toContain("[View job]");
+      expect(result).toContain("```\nFailed to fetch issue data\n```");
+      // Ensure error details come after the header/links
+      const errorIndex = result.indexOf("```");
+      const headerIndex = result.indexOf("**Claude encountered an error");
+      expect(errorIndex).toBeGreaterThan(headerIndex);
+    });
+
     it("handles username extraction from content when not provided", () => {
       const input = {
         ...baseInput,