Update agent mode to have github server as a default

src/modes/agent/index.ts

@@ -60,10 +60,27 @@ export const agentMode: Mode = {
     // Agent mode: User has full control via claudeArgs
     // No default tools are enforced - Claude Code's defaults will apply
 
-    // Agent mode uses a minimal MCP configuration
-    // We don't need comment servers or PR-specific tools for automation
+    // Always include the GitHub comment server in agent mode
+    // This ensures GitHub tools (PR reviews, comments, etc.) work out of the box
+    // without requiring users to manually configure the MCP server
     const mcpConfig: any = {
-      mcpServers: {},
+      mcpServers: {
+        "github-comment-server": {
+          command: "bun",
+          args: [
+            "run",
+            `${process.env.GITHUB_ACTION_PATH}/src/mcp/github-comment-server.ts`,
+          ],
+          env: {
+            GITHUB_TOKEN: process.env.GITHUB_TOKEN || "",
+            REPO_OWNER: context.repository.owner,
+            REPO_NAME: context.repository.repo,
+            GITHUB_EVENT_NAME: process.env.GITHUB_EVENT_NAME || "",
+            GITHUB_API_URL:
+              process.env.GITHUB_API_URL || "https://api.github.com",
+          },
+        },
+      },
     };
 
     // Add user-provided additional MCP config if any
@@ -72,16 +89,24 @@ export const agentMode: Mode = {
       try {
         const additional = JSON.parse(additionalMcpConfig);
         if (additional && typeof additional === "object") {
+          // Merge mcpServers if both have them
+          if (additional.mcpServers && mcpConfig.mcpServers) {
+            Object.assign(mcpConfig.mcpServers, additional.mcpServers);
+          } else {
             Object.assign(mcpConfig, additional);
           }
+        }
       } catch (error) {
         core.warning(`Failed to parse additional MCP config: ${error}`);
       }
     }
 
-    // Agent mode: pass through user's claude_args without modification
+    // Agent mode: pass through user's claude_args with MCP config
     const userClaudeArgs = process.env.CLAUDE_ARGS || "";
-    core.setOutput("claude_args", userClaudeArgs);
+    const escapedMcpConfig = JSON.stringify(mcpConfig).replace(/'/g, "'\\''");
+    const claudeArgs =
+      `--mcp-config '${escapedMcpConfig}' ${userClaudeArgs}`.trim();
+    core.setOutput("claude_args", claudeArgs);
 
     return {
       commentId: undefined,

test/modes/agent.test.ts

@@ -114,11 +114,11 @@ describe("Agent Mode", () => {
       githubToken: "test-token",
     });
 
-    // Verify claude_args is passed through
-    expect(setOutputSpy).toHaveBeenCalledWith(
-      "claude_args",
-      "--model claude-sonnet-4 --max-turns 10",
-    );
+    // Verify claude_args includes MCP config and user args
+    const callArgs = setOutputSpy.mock.calls[0];
+    expect(callArgs[0]).toBe("claude_args");
+    expect(callArgs[1]).toContain("--mcp-config");
+    expect(callArgs[1]).toContain("--model claude-sonnet-4 --max-turns 10");
 
     // Verify return structure
     expect(result).toEqual({
@@ -151,6 +151,9 @@ describe("Agent Mode", () => {
 
     // Note: We can't easily test file creation in this unit test,
     // but we can verify the method completes without errors
-    expect(setOutputSpy).toHaveBeenCalledWith("claude_args", "");
+    // Agent mode now includes MCP config even with empty user args
+    const callArgs = setOutputSpy.mock.calls[0];
+    expect(callArgs[0]).toBe("claude_args");
+    expect(callArgs[1]).toContain("--mcp-config");
   });
 });