diff --git a/.prettierignore b/.prettierignore
new file mode 100644
index 0000000..d62057c
--- /dev/null
+++ b/.prettierignore
@@ -0,0 +1,2 @@
+# Test fixtures should not be formatted to preserve exact output matching
+test/fixtures/
\ No newline at end of file
diff --git a/action.yml b/action.yml
index 8856cfc..ca5a7e9 100644
--- a/action.yml
+++ b/action.yml
@@ -191,10 +191,18 @@ runs:
       if: steps.prepare.outputs.contains_trigger == 'true' && steps.claude-code.outputs.execution_file != ''
       shell: bash
       run: |
-        echo "## Claude Code Report" >> $GITHUB_STEP_SUMMARY
-        echo '```json' >> $GITHUB_STEP_SUMMARY
-        cat "${{ steps.claude-code.outputs.execution_file }}" >> $GITHUB_STEP_SUMMARY
-        echo '```' >> $GITHUB_STEP_SUMMARY
+        # Try to format the turns, but if it fails, dump the raw JSON
+        if bun run ${{ github.action_path }}/src/entrypoints/format-turns.ts "${{ steps.claude-code.outputs.execution_file }}" >> $GITHUB_STEP_SUMMARY 2>/dev/null; then
+          echo "Successfully formatted Claude Code report"
+        else
+          echo "## Claude Code Report (Raw Output)" >> $GITHUB_STEP_SUMMARY
+          echo "" >> $GITHUB_STEP_SUMMARY
+          echo "Failed to format output (please report). Here's the raw JSON:" >> $GITHUB_STEP_SUMMARY
+          echo "" >> $GITHUB_STEP_SUMMARY
+          echo '```json' >> $GITHUB_STEP_SUMMARY
+          cat "${{ steps.claude-code.outputs.execution_file }}" >> $GITHUB_STEP_SUMMARY
+          echo '```' >> $GITHUB_STEP_SUMMARY
+        fi
 
     - name: Revoke app token
       if: always() && inputs.github_token == ''
diff --git a/src/entrypoints/format-turns.ts b/src/entrypoints/format-turns.ts
new file mode 100755
index 0000000..d136810
--- /dev/null
+++ b/src/entrypoints/format-turns.ts
@@ -0,0 +1,461 @@
+#!/usr/bin/env bun
+
+import { readFileSync, existsSync } from "fs";
+import { exit } from "process";
+
+export interface ToolUse {
+  type: string;
+  name?: string;
+  input?: Record<string, any>;
+  id?: string;
+}
+
+export interface ToolResult {
+  type: string;
+  tool_use_id?: string;
+  content?: any;
+  is_error?: boolean;
+}
+
+export interface ContentItem {
+  type: string;
+  text?: string;
+  tool_use_id?: string;
+  content?: any;
+  is_error?: boolean;
+  name?: string;
+  input?: Record<string, any>;
+  id?: string;
+}
+
+export interface Message {
+  content: ContentItem[];
+  usage?: {
+    input_tokens?: number;
+    output_tokens?: number;
+  };
+}
+
+export interface Turn {
+  type: string;
+  subtype?: string;
+  message?: Message;
+  tools?: any[];
+  cost_usd?: number;
+  duration_ms?: number;
+  result?: string;
+}
+
+export interface GroupedContent {
+  type: string;
+  tools_count?: number;
+  data?: Turn;
+  text_parts?: string[];
+  tool_calls?: { tool_use: ToolUse; tool_result?: ToolResult }[];
+  usage?: Record<string, number>;
+}
+
+export function detectContentType(content: any): string {
+  const contentStr = String(content).trim();
+
+  // Check for JSON
+  if (contentStr.startsWith("{") && contentStr.endsWith("}")) {
+    try {
+      JSON.parse(contentStr);
+      return "json";
+    } catch {
+      // Fall through
+    }
+  }
+
+  if (contentStr.startsWith("[") && contentStr.endsWith("]")) {
+    try {
+      JSON.parse(contentStr);
+      return "json";
+    } catch {
+      // Fall through
+    }
+  }
+
+  // Check for code-like content
+  const codeKeywords = [
+    "def ",
+    "class ",
+    "import ",
+    "from ",
+    "function ",
+    "const ",
+    "let ",
+    "var ",
+  ];
+  if (codeKeywords.some((keyword) => contentStr.includes(keyword))) {
+    if (
+      contentStr.includes("def ") ||
+      contentStr.includes("import ") ||
+      contentStr.includes("from ")
+    ) {
+      return "python";
+    } else if (
+      ["function ", "const ", "let ", "var ", "=>"].some((js) =>
+        contentStr.includes(js),
+      )
+    ) {
+      return "javascript";
+    } else {
+      return "python"; // default for code
+    }
+  }
+
+  // Check for shell/bash output
+  const shellIndicators = ["ls -", "cd ", "mkdir ", "rm ", "$ ", "# "];
+  if (
+    contentStr.startsWith("/") ||
+    contentStr.includes("Error:") ||
+    contentStr.startsWith("total ") ||
+    shellIndicators.some((indicator) => contentStr.includes(indicator))
+  ) {
+    return "bash";
+  }
+
+  // Check for diff format
+  if (
+    contentStr.startsWith("@@") ||
+    contentStr.includes("+++ ") ||
+    contentStr.includes("--- ")
+  ) {
+    return "diff";
+  }
+
+  // Check for HTML/XML
+  if (contentStr.startsWith("<") && contentStr.endsWith(">")) {
+    return "html";
+  }
+
+  // Check for markdown
+  const mdIndicators = ["# ", "## ", "### ", "- ", "* ", "```"];
+  if (mdIndicators.some((indicator) => contentStr.includes(indicator))) {
+    return "markdown";
+  }
+
+  // Default to plain text
+  return "text";
+}
+
+export function formatResultContent(content: any): string {
+  if (!content) {
+    return "*(No output)*\n\n";
+  }
+
+  let contentStr: string;
+
+  // Check if content is a list with "type": "text" structure
+  try {
+    let parsedContent: any;
+    if (typeof content === "string") {
+      parsedContent = JSON.parse(content);
+    } else {
+      parsedContent = content;
+    }
+
+    if (
+      Array.isArray(parsedContent) &&
+      parsedContent.length > 0 &&
+      typeof parsedContent[0] === "object" &&
+      parsedContent[0]?.type === "text"
+    ) {
+      // Extract the text field from the first item
+      contentStr = parsedContent[0]?.text || "";
+    } else {
+      contentStr = String(content).trim();
+    }
+  } catch {
+    contentStr = String(content).trim();
+  }
+
+  // Truncate very long results
+  if (contentStr.length > 3000) {
+    contentStr = contentStr.substring(0, 2997) + "...";
+  }
+
+  // Detect content type
+  const contentType = detectContentType(contentStr);
+
+  // Handle JSON content specially - pretty print it
+  if (contentType === "json") {
+    try {
+      // Try to parse and pretty print JSON
+      const parsed = JSON.parse(contentStr);
+      contentStr = JSON.stringify(parsed, null, 2);
+    } catch {
+      // Keep original if parsing fails
+    }
+  }
+
+  // Format with appropriate syntax highlighting
+  if (
+    contentType === "text" &&
+    contentStr.length < 100 &&
+    !contentStr.includes("\n")
+  ) {
+    // Short text results don't need code blocks
+    return `**→** ${contentStr}\n\n`;
+  } else {
+    return `**Result:**\n\`\`\`${contentType}\n${contentStr}\n\`\`\`\n\n`;
+  }
+}
+
+export function formatToolWithResult(
+  toolUse: ToolUse,
+  toolResult?: ToolResult,
+): string {
+  const toolName = toolUse.name || "unknown_tool";
+  const toolInput = toolUse.input || {};
+
+  let result = `### 🔧 \`${toolName}\`\n\n`;
+
+  // Add parameters if they exist and are not empty
+  if (Object.keys(toolInput).length > 0) {
+    result += "**Parameters:**\n```json\n";
+    result += JSON.stringify(toolInput, null, 2);
+    result += "\n```\n\n";
+  }
+
+  // Add result if available
+  if (toolResult) {
+    const content = toolResult.content || "";
+    const isError = toolResult.is_error || false;
+
+    if (isError) {
+      result += `❌ **Error:** \`${content}\`\n\n`;
+    } else {
+      result += formatResultContent(content);
+    }
+  }
+
+  return result;
+}
+
+export function groupTurnsNaturally(data: Turn[]): GroupedContent[] {
+  const groupedContent: GroupedContent[] = [];
+  const toolResultsMap = new Map<string, ToolResult>();
+
+  // First pass: collect all tool results by tool_use_id
+  for (const turn of data) {
+    if (turn.type === "user") {
+      const content = turn.message?.content || [];
+      for (const item of content) {
+        if (item.type === "tool_result" && item.tool_use_id) {
+          toolResultsMap.set(item.tool_use_id, {
+            type: item.type,
+            tool_use_id: item.tool_use_id,
+            content: item.content,
+            is_error: item.is_error,
+          });
+        }
+      }
+    }
+  }
+
+  // Second pass: process turns and group naturally
+  for (const turn of data) {
+    const turnType = turn.type || "unknown";
+
+    if (turnType === "system") {
+      const subtype = turn.subtype || "";
+      if (subtype === "init") {
+        const tools = turn.tools || [];
+        groupedContent.push({
+          type: "system_init",
+          tools_count: tools.length,
+        });
+      } else {
+        groupedContent.push({
+          type: "system_other",
+          data: turn,
+        });
+      }
+    } else if (turnType === "assistant") {
+      const message = turn.message || { content: [] };
+      const content = message.content || [];
+      const usage = message.usage || {};
+
+      // Process content items
+      const textParts: string[] = [];
+      const toolCalls: { tool_use: ToolUse; tool_result?: ToolResult }[] = [];
+
+      for (const item of content) {
+        const itemType = item.type || "";
+
+        if (itemType === "text") {
+          textParts.push(item.text || "");
+        } else if (itemType === "tool_use") {
+          const toolUseId = item.id;
+          const toolResult = toolUseId
+            ? toolResultsMap.get(toolUseId)
+            : undefined;
+          toolCalls.push({
+            tool_use: {
+              type: item.type,
+              name: item.name,
+              input: item.input,
+              id: item.id,
+            },
+            tool_result: toolResult,
+          });
+        }
+      }
+
+      if (textParts.length > 0 || toolCalls.length > 0) {
+        groupedContent.push({
+          type: "assistant_action",
+          text_parts: textParts,
+          tool_calls: toolCalls,
+          usage: usage,
+        });
+      }
+    } else if (turnType === "user") {
+      // Handle user messages that aren't tool results
+      const message = turn.message || { content: [] };
+      const content = message.content || [];
+      const textParts: string[] = [];
+
+      for (const item of content) {
+        if (item.type === "text") {
+          textParts.push(item.text || "");
+        }
+      }
+
+      if (textParts.length > 0) {
+        groupedContent.push({
+          type: "user_message",
+          text_parts: textParts,
+        });
+      }
+    } else if (turnType === "result") {
+      groupedContent.push({
+        type: "final_result",
+        data: turn,
+      });
+    }
+  }
+
+  return groupedContent;
+}
+
+export function formatGroupedContent(groupedContent: GroupedContent[]): string {
+  let markdown = "## Claude Code Report\n\n";
+
+  for (const item of groupedContent) {
+    const itemType = item.type;
+
+    if (itemType === "system_init") {
+      markdown += `## 🚀 System Initialization\n\n**Available Tools:** ${item.tools_count} tools loaded\n\n---\n\n`;
+    } else if (itemType === "system_other") {
+      markdown += `## ⚙️ System Message\n\n${JSON.stringify(item.data, null, 2)}\n\n---\n\n`;
+    } else if (itemType === "assistant_action") {
+      // Add text content first (if any) - no header needed
+      for (const text of item.text_parts || []) {
+        if (text.trim()) {
+          markdown += `${text}\n\n`;
+        }
+      }
+
+      // Add tool calls with their results
+      for (const toolCall of item.tool_calls || []) {
+        markdown += formatToolWithResult(
+          toolCall.tool_use,
+          toolCall.tool_result,
+        );
+      }
+
+      // Add usage info if available
+      const usage = item.usage || {};
+      if (Object.keys(usage).length > 0) {
+        const inputTokens = usage.input_tokens || 0;
+        const outputTokens = usage.output_tokens || 0;
+        markdown += `*Token usage: ${inputTokens} input, ${outputTokens} output*\n\n`;
+      }
+
+      // Only add separator if this section had content
+      if (
+        (item.text_parts && item.text_parts.length > 0) ||
+        (item.tool_calls && item.tool_calls.length > 0)
+      ) {
+        markdown += "---\n\n";
+      }
+    } else if (itemType === "user_message") {
+      markdown += "## 👤 User\n\n";
+      for (const text of item.text_parts || []) {
+        if (text.trim()) {
+          markdown += `${text}\n\n`;
+        }
+      }
+      markdown += "---\n\n";
+    } else if (itemType === "final_result") {
+      const data = item.data || {};
+      const cost = (data as any).cost_usd || 0;
+      const duration = (data as any).duration_ms || 0;
+      const resultText = (data as any).result || "";
+
+      markdown += "## ✅ Final Result\n\n";
+      if (resultText) {
+        markdown += `${resultText}\n\n`;
+      }
+      markdown += `**Cost:** $${cost.toFixed(4)} | **Duration:** ${(duration / 1000).toFixed(1)}s\n\n`;
+    }
+  }
+
+  return markdown;
+}
+
+export function formatTurnsFromData(data: Turn[]): string {
+  // Group turns naturally
+  const groupedContent = groupTurnsNaturally(data);
+
+  // Generate markdown
+  const markdown = formatGroupedContent(groupedContent);
+
+  return markdown;
+}
+
+function main(): void {
+  // Get the JSON file path from command line arguments
+  const args = process.argv.slice(2);
+  if (args.length === 0) {
+    console.error("Usage: format-turns.ts <json-file>");
+    exit(1);
+  }
+
+  const jsonFile = args[0];
+  if (!jsonFile) {
+    console.error("Error: No JSON file provided");
+    exit(1);
+  }
+
+  if (!existsSync(jsonFile)) {
+    console.error(`Error: ${jsonFile} not found`);
+    exit(1);
+  }
+
+  try {
+    // Read the JSON file
+    const fileContent = readFileSync(jsonFile, "utf-8");
+    const data: Turn[] = JSON.parse(fileContent);
+
+    // Group turns naturally
+    const groupedContent = groupTurnsNaturally(data);
+
+    // Generate markdown
+    const markdown = formatGroupedContent(groupedContent);
+
+    // Print to stdout (so it can be captured by shell)
+    console.log(markdown);
+  } catch (error) {
+    console.error(`Error processing file: ${error}`);
+    exit(1);
+  }
+}
+
+if (import.meta.main) {
+  main();
+}
diff --git a/test/fixtures/sample-turns-expected-output.md b/test/fixtures/sample-turns-expected-output.md
new file mode 100644
index 0000000..82c506d
--- /dev/null
+++ b/test/fixtures/sample-turns-expected-output.md
@@ -0,0 +1,95 @@
+## Claude Code Report
+
+## 🚀 System Initialization
+
+**Available Tools:** 8 tools loaded
+
+---
+
+I'll help you with this task. Let me start by examining the file to understand what needs to be changed.
+
+### 🔧 `Read`
+
+**Parameters:**
+```json
+{
+  "file_path": "/path/to/sample/file.py"
+}
+```
+
+**Result:**
+```python
+def example_function():
+    print("Debug message")  # This should be removed
+    return "Hello World"
+
+if __name__ == "__main__":
+    result = example_function()
+    print(result)
+```
+
+*Token usage: 100 input, 75 output*
+
+---
+
+I can see the debug print statement that needs to be removed. Let me fix this by editing the file.
+
+### 🔧 `Edit`
+
+**Parameters:**
+```json
+{
+  "file_path": "/path/to/sample/file.py",
+  "old_string": "def example_function():\n    print(\"Debug message\")  # This should be removed\n    return \"Hello World\"",
+  "new_string": "def example_function():\n    return \"Hello World\""
+}
+```
+
+**→** File successfully edited. The debug print statement has been removed.
+
+*Token usage: 200 input, 50 output*
+
+---
+
+Perfect! I've successfully removed the debug print statement from the function. Let me now create a pull request comment to document this change.
+
+### 🔧 `mcp__github__add_pull_request_review_comment`
+
+**Parameters:**
+```json
+{
+  "owner": "example-org",
+  "repo": "example-repo",
+  "pull_number": 123,
+  "body": "Removed debug print statement as requested.",
+  "commit_id": "abc123def456",
+  "path": "sample/file.py",
+  "line": 2
+}
+```
+
+**→** Successfully posted review comment to PR #123
+
+*Token usage: 150 input, 80 output*
+
+---
+
+Great! I've successfully completed the requested task:
+
+1. ✅ Located the debug print statement in the file
+2. ✅ Removed the print statement while preserving the function logic
+3. ✅ Added a review comment documenting the change
+
+The debug print statement has been removed as requested by the reviewers.
+
+*Token usage: 180 input, 60 output*
+
+---
+
+## ✅ Final Result
+
+Successfully removed debug print statement from file and added review comment to document the change.
+
+**Cost:** $0.0347 | **Duration:** 18.8s
+
+
diff --git a/test/fixtures/sample-turns.json b/test/fixtures/sample-turns.json
new file mode 100644
index 0000000..2690675
--- /dev/null
+++ b/test/fixtures/sample-turns.json
@@ -0,0 +1,196 @@
+[
+  {
+    "type": "system",
+    "subtype": "init",
+    "session_id": "sample-session-id",
+    "tools": [
+      "Task",
+      "Bash",
+      "Read",
+      "Edit",
+      "Write",
+      "mcp__github__get_file_contents",
+      "mcp__github__create_or_update_file",
+      "mcp__github__add_pull_request_review_comment"
+    ],
+    "mcp_servers": [
+      {
+        "name": "github",
+        "status": "connected"
+      }
+    ]
+  },
+  {
+    "type": "assistant",
+    "message": {
+      "id": "msg_sample123",
+      "type": "message",
+      "role": "assistant",
+      "model": "claude-test-model",
+      "content": [
+        {
+          "type": "text",
+          "text": "I'll help you with this task. Let me start by examining the file to understand what needs to be changed."
+        },
+        {
+          "type": "tool_use",
+          "id": "tool_call_1",
+          "name": "Read",
+          "input": {
+            "file_path": "/path/to/sample/file.py"
+          }
+        }
+      ],
+      "stop_reason": "tool_use",
+      "stop_sequence": null,
+      "usage": {
+        "input_tokens": 100,
+        "cache_creation_input_tokens": 0,
+        "cache_read_input_tokens": 50,
+        "output_tokens": 75
+      }
+    },
+    "session_id": "sample-session-id"
+  },
+  {
+    "type": "user",
+    "message": {
+      "content": [
+        {
+          "type": "tool_result",
+          "tool_use_id": "tool_call_1",
+          "content": "def example_function():\n    print(\"Debug message\")  # This should be removed\n    return \"Hello World\"\n\nif __name__ == \"__main__\":\n    result = example_function()\n    print(result)",
+          "is_error": false
+        }
+      ]
+    }
+  },
+  {
+    "type": "assistant",
+    "message": {
+      "id": "msg_sample124",
+      "type": "message",
+      "role": "assistant",
+      "model": "claude-test-model",
+      "content": [
+        {
+          "type": "text",
+          "text": "I can see the debug print statement that needs to be removed. Let me fix this by editing the file."
+        },
+        {
+          "type": "tool_use",
+          "id": "tool_call_2",
+          "name": "Edit",
+          "input": {
+            "file_path": "/path/to/sample/file.py",
+            "old_string": "def example_function():\n    print(\"Debug message\")  # This should be removed\n    return \"Hello World\"",
+            "new_string": "def example_function():\n    return \"Hello World\""
+          }
+        }
+      ],
+      "stop_reason": "tool_use",
+      "stop_sequence": null,
+      "usage": {
+        "input_tokens": 200,
+        "cache_creation_input_tokens": 0,
+        "cache_read_input_tokens": 100,
+        "output_tokens": 50
+      }
+    },
+    "session_id": "sample-session-id"
+  },
+  {
+    "type": "user",
+    "message": {
+      "content": [
+        {
+          "type": "tool_result",
+          "tool_use_id": "tool_call_2",
+          "content": "File successfully edited. The debug print statement has been removed.",
+          "is_error": false
+        }
+      ]
+    }
+  },
+  {
+    "type": "assistant",
+    "message": {
+      "id": "msg_sample125",
+      "type": "message",
+      "role": "assistant",
+      "model": "claude-test-model",
+      "content": [
+        {
+          "type": "text",
+          "text": "Perfect! I've successfully removed the debug print statement from the function. Let me now create a pull request comment to document this change."
+        },
+        {
+          "type": "tool_use",
+          "id": "tool_call_3",
+          "name": "mcp__github__add_pull_request_review_comment",
+          "input": {
+            "owner": "example-org",
+            "repo": "example-repo",
+            "pull_number": 123,
+            "body": "Removed debug print statement as requested.",
+            "commit_id": "abc123def456",
+            "path": "sample/file.py",
+            "line": 2
+          }
+        }
+      ],
+      "stop_reason": "tool_use",
+      "stop_sequence": null,
+      "usage": {
+        "input_tokens": 150,
+        "cache_creation_input_tokens": 0,
+        "cache_read_input_tokens": 75,
+        "output_tokens": 80
+      }
+    },
+    "session_id": "sample-session-id"
+  },
+  {
+    "type": "user",
+    "message": {
+      "content": [
+        {
+          "type": "tool_result",
+          "tool_use_id": "tool_call_3",
+          "content": "Successfully posted review comment to PR #123",
+          "is_error": false
+        }
+      ]
+    }
+  },
+  {
+    "type": "assistant",
+    "message": {
+      "id": "msg_sample126",
+      "type": "message",
+      "role": "assistant",
+      "model": "claude-test-model",
+      "content": [
+        {
+          "type": "text",
+          "text": "Great! I've successfully completed the requested task:\n\n1. ✅ Located the debug print statement in the file\n2. ✅ Removed the print statement while preserving the function logic\n3. ✅ Added a review comment documenting the change\n\nThe debug print statement has been removed as requested by the reviewers."
+        }
+      ],
+      "stop_reason": "end_turn",
+      "stop_sequence": null,
+      "usage": {
+        "input_tokens": 180,
+        "cache_creation_input_tokens": 0,
+        "cache_read_input_tokens": 90,
+        "output_tokens": 60
+      }
+    },
+    "session_id": "sample-session-id"
+  },
+  {
+    "type": "result",
+    "cost_usd": 0.0347,
+    "duration_ms": 18750,
+    "result": "Successfully removed debug print statement from file and added review comment to document the change."
+  }
+]
diff --git a/test/format-turns.test.ts b/test/format-turns.test.ts
new file mode 100644
index 0000000..bb26f2e
--- /dev/null
+++ b/test/format-turns.test.ts
@@ -0,0 +1,439 @@
+import { expect, test, describe } from "bun:test";
+import { readFileSync } from "fs";
+import { join } from "path";
+import {
+  formatTurnsFromData,
+  groupTurnsNaturally,
+  formatGroupedContent,
+  detectContentType,
+  formatResultContent,
+  formatToolWithResult,
+  type Turn,
+  type ToolUse,
+  type ToolResult,
+} from "../src/entrypoints/format-turns";
+
+describe("detectContentType", () => {
+  test("detects JSON objects", () => {
+    expect(detectContentType('{"key": "value"}')).toBe("json");
+    expect(detectContentType('{"number": 42}')).toBe("json");
+  });
+
+  test("detects JSON arrays", () => {
+    expect(detectContentType("[1, 2, 3]")).toBe("json");
+    expect(detectContentType('["a", "b"]')).toBe("json");
+  });
+
+  test("detects Python code", () => {
+    expect(detectContentType("def hello():\n    pass")).toBe("python");
+    expect(detectContentType("import os")).toBe("python");
+    expect(detectContentType("from math import pi")).toBe("python");
+  });
+
+  test("detects JavaScript code", () => {
+    expect(detectContentType("function test() {}")).toBe("javascript");
+    expect(detectContentType("const x = 5")).toBe("javascript");
+    expect(detectContentType("let y = 10")).toBe("javascript");
+    expect(detectContentType("const fn = () => console.log()")).toBe(
+      "javascript",
+    );
+  });
+
+  test("detects bash/shell content", () => {
+    expect(detectContentType("/usr/bin/test")).toBe("bash");
+    expect(detectContentType("Error: command not found")).toBe("bash");
+    expect(detectContentType("ls -la")).toBe("bash");
+    expect(detectContentType("$ echo hello")).toBe("bash");
+  });
+
+  test("detects diff format", () => {
+    expect(detectContentType("@@ -1,3 +1,3 @@")).toBe("diff");
+    expect(detectContentType("+++ file.txt")).toBe("diff");
+    expect(detectContentType("--- file.txt")).toBe("diff");
+  });
+
+  test("detects HTML/XML", () => {
+    expect(detectContentType("<div>hello</div>")).toBe("html");
+    expect(detectContentType("<xml>content</xml>")).toBe("html");
+  });
+
+  test("detects markdown", () => {
+    expect(detectContentType("- List item")).toBe("markdown");
+    expect(detectContentType("* List item")).toBe("markdown");
+    expect(detectContentType("```code```")).toBe("markdown");
+  });
+
+  test("defaults to text", () => {
+    expect(detectContentType("plain text")).toBe("text");
+    expect(detectContentType("just some words")).toBe("text");
+  });
+});
+
+describe("formatResultContent", () => {
+  test("handles empty content", () => {
+    expect(formatResultContent("")).toBe("*(No output)*\n\n");
+    expect(formatResultContent(null)).toBe("*(No output)*\n\n");
+    expect(formatResultContent(undefined)).toBe("*(No output)*\n\n");
+  });
+
+  test("formats short text without code blocks", () => {
+    const result = formatResultContent("success");
+    expect(result).toBe("**→** success\n\n");
+  });
+
+  test("formats long text with code blocks", () => {
+    const longText =
+      "This is a longer piece of text that should be formatted in a code block because it exceeds the short text threshold";
+    const result = formatResultContent(longText);
+    expect(result).toContain("**Result:**");
+    expect(result).toContain("```text");
+    expect(result).toContain(longText);
+  });
+
+  test("pretty prints JSON content", () => {
+    const jsonContent = '{"key": "value", "number": 42}';
+    const result = formatResultContent(jsonContent);
+    expect(result).toContain("```json");
+    expect(result).toContain('"key": "value"');
+    expect(result).toContain('"number": 42');
+  });
+
+  test("truncates very long content", () => {
+    const veryLongContent = "A".repeat(4000);
+    const result = formatResultContent(veryLongContent);
+    expect(result).toContain("...");
+    // Should not contain the full long content
+    expect(result.length).toBeLessThan(veryLongContent.length);
+  });
+
+  test("handles type:text structure", () => {
+    const structuredContent = [{ type: "text", text: "Hello world" }];
+    const result = formatResultContent(JSON.stringify(structuredContent));
+    expect(result).toBe("**→** Hello world\n\n");
+  });
+});
+
+describe("formatToolWithResult", () => {
+  test("formats tool with parameters and result", () => {
+    const toolUse: ToolUse = {
+      type: "tool_use",
+      name: "read_file",
+      input: { file_path: "/path/to/file.txt" },
+      id: "tool_123",
+    };
+
+    const toolResult: ToolResult = {
+      type: "tool_result",
+      tool_use_id: "tool_123",
+      content: "File content here",
+      is_error: false,
+    };
+
+    const result = formatToolWithResult(toolUse, toolResult);
+
+    expect(result).toContain("### 🔧 `read_file`");
+    expect(result).toContain("**Parameters:**");
+    expect(result).toContain('"file_path": "/path/to/file.txt"');
+    expect(result).toContain("**→** File content here");
+  });
+
+  test("formats tool with error result", () => {
+    const toolUse: ToolUse = {
+      type: "tool_use",
+      name: "failing_tool",
+      input: { param: "value" },
+    };
+
+    const toolResult: ToolResult = {
+      type: "tool_result",
+      content: "Permission denied",
+      is_error: true,
+    };
+
+    const result = formatToolWithResult(toolUse, toolResult);
+
+    expect(result).toContain("### 🔧 `failing_tool`");
+    expect(result).toContain("❌ **Error:** `Permission denied`");
+  });
+
+  test("formats tool without parameters", () => {
+    const toolUse: ToolUse = {
+      type: "tool_use",
+      name: "simple_tool",
+    };
+
+    const result = formatToolWithResult(toolUse);
+
+    expect(result).toContain("### 🔧 `simple_tool`");
+    expect(result).not.toContain("**Parameters:**");
+  });
+
+  test("handles unknown tool name", () => {
+    const toolUse: ToolUse = {
+      type: "tool_use",
+    };
+
+    const result = formatToolWithResult(toolUse);
+
+    expect(result).toContain("### 🔧 `unknown_tool`");
+  });
+});
+
+describe("groupTurnsNaturally", () => {
+  test("groups system initialization", () => {
+    const data: Turn[] = [
+      {
+        type: "system",
+        subtype: "init",
+        tools: [{ name: "tool1" }, { name: "tool2" }],
+      },
+    ];
+
+    const result = groupTurnsNaturally(data);
+
+    expect(result).toHaveLength(1);
+    expect(result[0]?.type).toBe("system_init");
+    expect(result[0]?.tools_count).toBe(2);
+  });
+
+  test("groups assistant actions with tool calls", () => {
+    const data: Turn[] = [
+      {
+        type: "assistant",
+        message: {
+          content: [
+            { type: "text", text: "I'll help you" },
+            {
+              type: "tool_use",
+              id: "tool_123",
+              name: "read_file",
+              input: { file_path: "/test.txt" },
+            },
+          ],
+          usage: { input_tokens: 100, output_tokens: 50 },
+        },
+      },
+      {
+        type: "user",
+        message: {
+          content: [
+            {
+              type: "tool_result",
+              tool_use_id: "tool_123",
+              content: "file content",
+              is_error: false,
+            },
+          ],
+        },
+      },
+    ];
+
+    const result = groupTurnsNaturally(data);
+
+    expect(result).toHaveLength(1);
+    expect(result[0]?.type).toBe("assistant_action");
+    expect(result[0]?.text_parts).toEqual(["I'll help you"]);
+    expect(result[0]?.tool_calls).toHaveLength(1);
+    expect(result[0]?.tool_calls?.[0]?.tool_use.name).toBe("read_file");
+    expect(result[0]?.tool_calls?.[0]?.tool_result?.content).toBe(
+      "file content",
+    );
+    expect(result[0]?.usage).toEqual({ input_tokens: 100, output_tokens: 50 });
+  });
+
+  test("groups user messages", () => {
+    const data: Turn[] = [
+      {
+        type: "user",
+        message: {
+          content: [{ type: "text", text: "Please help me" }],
+        },
+      },
+    ];
+
+    const result = groupTurnsNaturally(data);
+
+    expect(result).toHaveLength(1);
+    expect(result[0]?.type).toBe("user_message");
+    expect(result[0]?.text_parts).toEqual(["Please help me"]);
+  });
+
+  test("groups final results", () => {
+    const data: Turn[] = [
+      {
+        type: "result",
+        cost_usd: 0.1234,
+        duration_ms: 5000,
+        result: "Task completed",
+      },
+    ];
+
+    const result = groupTurnsNaturally(data);
+
+    expect(result).toHaveLength(1);
+    expect(result[0]?.type).toBe("final_result");
+    expect(result[0]?.data).toEqual(data[0]!);
+  });
+});
+
+describe("formatGroupedContent", () => {
+  test("formats system initialization", () => {
+    const groupedContent = [
+      {
+        type: "system_init",
+        tools_count: 3,
+      },
+    ];
+
+    const result = formatGroupedContent(groupedContent);
+
+    expect(result).toContain("## Claude Code Report");
+    expect(result).toContain("## 🚀 System Initialization");
+    expect(result).toContain("**Available Tools:** 3 tools loaded");
+  });
+
+  test("formats assistant actions", () => {
+    const groupedContent = [
+      {
+        type: "assistant_action",
+        text_parts: ["I'll help you with that"],
+        tool_calls: [
+          {
+            tool_use: {
+              type: "tool_use",
+              name: "test_tool",
+              input: { param: "value" },
+            },
+            tool_result: {
+              type: "tool_result",
+              content: "result",
+              is_error: false,
+            },
+          },
+        ],
+        usage: { input_tokens: 100, output_tokens: 50 },
+      },
+    ];
+
+    const result = formatGroupedContent(groupedContent);
+
+    expect(result).toContain("I'll help you with that");
+    expect(result).toContain("### 🔧 `test_tool`");
+    expect(result).toContain("*Token usage: 100 input, 50 output*");
+  });
+
+  test("formats user messages", () => {
+    const groupedContent = [
+      {
+        type: "user_message",
+        text_parts: ["Help me please"],
+      },
+    ];
+
+    const result = formatGroupedContent(groupedContent);
+
+    expect(result).toContain("## 👤 User");
+    expect(result).toContain("Help me please");
+  });
+
+  test("formats final results", () => {
+    const groupedContent = [
+      {
+        type: "final_result",
+        data: {
+          type: "result",
+          cost_usd: 0.1234,
+          duration_ms: 5678,
+          result: "Success!",
+        } as Turn,
+      },
+    ];
+
+    const result = formatGroupedContent(groupedContent);
+
+    expect(result).toContain("## ✅ Final Result");
+    expect(result).toContain("Success!");
+    expect(result).toContain("**Cost:** $0.1234");
+    expect(result).toContain("**Duration:** 5.7s");
+  });
+});
+
+describe("formatTurnsFromData", () => {
+  test("handles empty data", () => {
+    const result = formatTurnsFromData([]);
+    expect(result).toBe("## Claude Code Report\n\n");
+  });
+
+  test("formats complete conversation", () => {
+    const data: Turn[] = [
+      {
+        type: "system",
+        subtype: "init",
+        tools: [{ name: "tool1" }],
+      },
+      {
+        type: "assistant",
+        message: {
+          content: [
+            { type: "text", text: "I'll help you" },
+            {
+              type: "tool_use",
+              id: "tool_123",
+              name: "read_file",
+              input: { file_path: "/test.txt" },
+            },
+          ],
+        },
+      },
+      {
+        type: "user",
+        message: {
+          content: [
+            {
+              type: "tool_result",
+              tool_use_id: "tool_123",
+              content: "file content",
+              is_error: false,
+            },
+          ],
+        },
+      },
+      {
+        type: "result",
+        cost_usd: 0.05,
+        duration_ms: 2000,
+        result: "Done",
+      },
+    ];
+
+    const result = formatTurnsFromData(data);
+
+    expect(result).toContain("## Claude Code Report");
+    expect(result).toContain("## 🚀 System Initialization");
+    expect(result).toContain("I'll help you");
+    expect(result).toContain("### 🔧 `read_file`");
+    expect(result).toContain("## ✅ Final Result");
+    expect(result).toContain("Done");
+  });
+});
+
+describe("integration tests", () => {
+  test("formats real conversation data correctly", () => {
+    // Load the sample JSON data
+    const jsonPath = join(__dirname, "fixtures", "sample-turns.json");
+    const expectedPath = join(
+      __dirname,
+      "fixtures",
+      "sample-turns-expected-output.md",
+    );
+
+    const jsonData = JSON.parse(readFileSync(jsonPath, "utf-8"));
+    const expectedOutput = readFileSync(expectedPath, "utf-8").trim();
+
+    // Format the data using our function
+    const actualOutput = formatTurnsFromData(jsonData).trim();
+
+    // Compare the outputs
+    expect(actualOutput).toBe(expectedOutput);
+  });
+});