diff --git a/apps/frontend/src/main/ipc-handlers/github/investigation-handlers.ts b/apps/frontend/src/main/ipc-handlers/github/investigation-handlers.ts
index bcbc71af..11c129d3 100644
--- a/apps/frontend/src/main/ipc-handlers/github/investigation-handlers.ts
+++ b/apps/frontend/src/main/ipc-handlers/github/investigation-handlers.ts
@@ -1173,12 +1173,16 @@ async function runInvestigation(
         // Non-fatal: will start fresh
       }
 
+      // Read investigation settings to get fastInvestigations flag
+      const investigationSettings = getInvestigationSettings(projectId);
+
       const args = [
         ...buildRunnerArgs(
           getRunnerPath(backendPath),
           project.path,
           'investigate',
           [String(issueNumber)],
+          { fastMode: investigationSettings.fastInvestigations ?? false },
         ),
         '--specialist-config', JSON.stringify(specialistConfig),
         ...resumeSessionsArg,
diff --git a/apps/frontend/src/main/ipc-handlers/github/utils/subprocess-runner.ts b/apps/frontend/src/main/ipc-handlers/github/utils/subprocess-runner.ts
index e1c181ec..f6cd5531 100644
--- a/apps/frontend/src/main/ipc-handlers/github/utils/subprocess-runner.ts
+++ b/apps/frontend/src/main/ipc-handlers/github/utils/subprocess-runner.ts
@@ -765,6 +765,7 @@ export function buildRunnerArgs(
   options?: {
     model?: string;
     thinkingLevel?: string;
+    fastMode?: boolean;
   }
 ): string[] {
   const args = [runnerPath, '--project', projectPath];
@@ -777,6 +778,10 @@ export function buildRunnerArgs(
     args.push('--thinking-level', options.thinkingLevel);
   }
 
+  if (options?.fastMode) {
+    args.push('--fast-mode');
+  }
+
   args.push(command);
   args.push(...additionalArgs);