feat(tui): let Esc cancel active minimal-mode response generation

src/frontends/tui/minimal.test.ts

@@ -29,6 +29,7 @@ function asAgent(value: unknown): NativeAgent {
 function minimalTuiPrivates(value: MinimalTui): {
   handleBackendCommand: (provider: string) => Promise<void>;
   handleModelCommand: (tier: string, providerModel?: string) => void;
+  handleEscapeAction: () => boolean;
   prompt: (text: string) => Promise<string>;
   rl: {
     once: (event: string, cb: () => void) => void;
@@ -37,10 +38,12 @@ function minimalTuiPrivates(value: MinimalTui): {
     write: (data: string | null, key?: { ctrl?: boolean; name?: string }) => void;
   };
   activePromptCancel: (() => void) | null;
+  activeOperationCancel: (() => void) | null;
 } {
   return value as unknown as {
     handleBackendCommand: (provider: string) => Promise<void>;
     handleModelCommand: (tier: string, providerModel?: string) => void;
+    handleEscapeAction: () => boolean;
     prompt: (text: string) => Promise<string>;
     rl: {
       once: (event: string, cb: () => void) => void;
@@ -49,6 +52,7 @@ function minimalTuiPrivates(value: MinimalTui): {
       write: (data: string | null, key?: { ctrl?: boolean; name?: string }) => void;
     };
     activePromptCancel: (() => void) | null;
+    activeOperationCancel: (() => void) | null;
   };
 }
 
@@ -329,4 +333,26 @@ describe('MinimalTui prompt cancellation', () => {
     expect(write).toHaveBeenCalledWith(null, { name: 'return' });
     expect(minimalTuiPrivates(tui).activePromptCancel).toBeNull();
   });
+
+  it('uses Esc to cancel active running operation', () => {
+    const mockSession = {
+      id: 'test',
+      getHistory: () => [],
+      addMessage: vi.fn(),
+      clear: vi.fn(),
+      replaceHistory: vi.fn(),
+    };
+
+    const tui = new MinimalTui({
+      session: asSession(mockSession),
+      modelClient: asRouter({}),
+      systemPrompt: 'test',
+    });
+
+    const cancelRunningOperation = vi.fn();
+    minimalTuiPrivates(tui).activeOperationCancel = cancelRunningOperation;
+
+    expect(minimalTuiPrivates(tui).handleEscapeAction()).toBe(true);
+    expect(cancelRunningOperation).toHaveBeenCalledOnce();
+  });
 });

src/frontends/tui/minimal.ts

@@ -76,6 +76,7 @@ export class MinimalTui {
   private currentHint = '';
   private lastLine = '';
   private activePromptCancel: (() => void) | null = null;
+  private activeOperationCancel: (() => void) | null = null;
   private keypressHandler: ((char: string, key: readline.Key) => void) | null = null;
 
   constructor(private config: MinimalTuiConfig) {}
@@ -84,6 +85,29 @@ export class MinimalTui {
     return key?.name === 'escape' || key?.sequence === '\x1b' || char === '\x1b';
   }
 
+  private handleEscapeAction(): boolean {
+    if (this.activePromptCancel) {
+      this.activePromptCancel();
+      return true;
+    }
+
+    if (this.activeOperationCancel) {
+      this.activeOperationCancel();
+      return true;
+    }
+
+    if (this.rl) {
+      try {
+        this.rl.write(null, { ctrl: true, name: 'u' });
+      } catch {
+        // ignore
+      }
+      return true;
+    }
+
+    return false;
+  }
+
   private showHint(line: string): void {
     if (!line.startsWith('/')) {
       this.clearHint();
@@ -164,17 +188,7 @@ export class MinimalTui {
     // Listen for line changes to show hints
     this.keypressHandler = (char: string, key: readline.Key) => {
       if (this.isEscapeKey(char, key)) {
-        if (this.activePromptCancel) {
-          this.activePromptCancel();
-          return;
-        }
-        if (this.rl) {
-          try {
-            this.rl.write(null, { ctrl: true, name: 'u' });
-          } catch {
-            // ignore
-          }
-        }
+        this.handleEscapeAction();
         return;
       }
 
@@ -198,7 +212,7 @@ export class MinimalTui {
 
     console.log(getColoredBanner());
     console.log(`\n${colors.orange}${colors.bold}Flynn TUI${colors.reset} ${colors.dim}(minimal mode)${colors.reset}`);
-    console.log(`${colors.gray}Type /help for commands, /fullscreen for panel mode, Esc to cancel prompts${colors.reset}\n`);
+    console.log(`${colors.gray}Type /help for commands, /fullscreen for panel mode, Esc to cancel prompts or running responses${colors.reset}\n`);
 
     await this.promptLoop();
   }
@@ -917,7 +931,17 @@ export class MinimalTui {
     try {
       // Use agent if available (supports tool loop)
       if (this.config.agent) {
+        let cancelRequested = false;
+        this.activeOperationCancel = () => {
+          if (cancelRequested) {
+            return;
+          }
+          cancelRequested = true;
+          this.config.agent?.cancel();
+          console.log(`\n${colors.gray}Cancelling...${colors.reset}`);
+        };
         const response = await this.config.agent.process(content);
+        this.activeOperationCancel = null;
         const rendered = renderMarkdown(response);
         console.log(rendered);
         console.log();
@@ -930,11 +954,23 @@ export class MinimalTui {
       // Try streaming if available
       if (this.config.modelClient.chatStream) {
         let fullContent = '';
+        let cancelRequested = false;
+        this.activeOperationCancel = () => {
+          if (cancelRequested) {
+            return;
+          }
+          cancelRequested = true;
+          console.log(`\n${colors.gray}Cancelling...${colors.reset}`);
+        };
 
         for await (const event of this.config.modelClient.chatStream({
           messages: this.config.session.getHistory(),
           system: this.config.systemPrompt,
         })) {
+          if (cancelRequested) {
+            fullContent += '\n\n[interrupted]';
+            break;
+          }
           if (event.type === 'content' && event.content) {
             process.stdout.write(event.content);
             fullContent += event.content;
@@ -950,16 +986,21 @@ export class MinimalTui {
             throw event.error ?? new Error('Stream error');
           }
         }
+        this.activeOperationCancel = null;
 
         console.log('\n');
 
         this.config.session.addMessage({ role: 'assistant', content: fullContent });
       } else {
+        this.activeOperationCancel = () => {
+          console.log(`\n${colors.gray}Cancellation is not available for non-streaming responses.${colors.reset}`);
+        };
         // Fallback to non-streaming
         const response = await this.config.modelClient.chat({
           messages: this.config.session.getHistory(),
           system: this.config.systemPrompt,
         });
+        this.activeOperationCancel = null;
 
         const rendered = renderMarkdown(response.content);
         console.log(rendered);
@@ -973,12 +1014,15 @@ export class MinimalTui {
     } catch (error) {
       console.error('Error:', error instanceof Error ? error.message : error);
       console.log();
+    } finally {
+      this.activeOperationCancel = null;
     }
   }
 
   stop(preserveStdin = false): void {
     this.running = false;
     this.activePromptCancel = null;
+    this.activeOperationCancel = null;
     if (this.rl) {
       if (preserveStdin) {
         // Remove readline listeners but don't close stdin