diff --git a/base-action/src/parse-sdk-options.ts b/base-action/src/parse-sdk-options.ts
index f101383..7b619f3 100644
--- a/base-action/src/parse-sdk-options.ts
+++ b/base-action/src/parse-sdk-options.ts
@@ -101,7 +101,7 @@ export function parseSdkOptions(options: ClaudeOptions): ParsedSdkOptions {
     env.GITHUB_ACTION_INPUTS = process.env.INPUT_ACTION_INPUTS_PRESENT;
   }
 
-  // Build system prompt option
+  // Build system prompt option - default to claude_code preset
   let systemPrompt: SdkOptions["systemPrompt"];
   if (options.systemPrompt) {
     systemPrompt = options.systemPrompt;
@@ -111,6 +111,12 @@ export function parseSdkOptions(options: ClaudeOptions): ParsedSdkOptions {
       preset: "claude_code",
       append: options.appendSystemPrompt,
     };
+  } else {
+    // Default to claude_code preset when no custom prompt is specified
+    systemPrompt = {
+      type: "preset",
+      preset: "claude_code",
+    };
   }
 
   // Build SDK options - use merged tools from both direct options and claudeArgs
@@ -130,6 +136,9 @@ export function parseSdkOptions(options: ClaudeOptions): ParsedSdkOptions {
     // Note: allowedTools and disallowedTools have been removed from extraArgs to prevent duplicates
     extraArgs,
     env,
+
+    // Load settings from all sources to pick up CLI-installed plugins, CLAUDE.md, etc.
+    settingSources: ["user", "project", "local"],
   };
 
   return {
diff --git a/base-action/src/run-claude-sdk.ts b/base-action/src/run-claude-sdk.ts
index cea7035..2bf0b24 100644
--- a/base-action/src/run-claude-sdk.ts
+++ b/base-action/src/run-claude-sdk.ts
@@ -75,6 +75,9 @@ export async function runClaudeWithSdk(
   }
 
   console.log(`Running Claude with prompt from file: ${promptPath}`);
+  // Log SDK options without env (which could contain sensitive data)
+  const { env, ...optionsToLog } = sdkOptions;
+  console.log("SDK options:", JSON.stringify(optionsToLog, null, 2));
 
   const messages: SDKMessage[] = [];
   let resultMessage: SDKResultMessage | undefined;