replace input instead of appending on autocomplete

Author: iscekic

cli/src/state/atoms/__tests__/keyboard.test.ts

@@ -359,7 +359,7 @@ describe("keypress atoms", () => {
 			expect(text).toBe("/mode")
 		})
 
-		it("should complete argument by appending only missing part", () => {
+		it("should complete argument by replacing partial text", () => {
 			// Type '/mode tes' - this will automatically trigger autocomplete
 			const input = "/mode tes"
 			for (const char of input) {
@@ -398,11 +398,96 @@ describe("keypress atoms", () => {
 			}
 			store.set(keyboardHandlerAtom, tabKey)
 
-			// Should append only 't' to complete '/mode test'
+			// Should replace 'tes' with 'test' to complete '/mode test'
 			const text = store.get(textBufferStringAtom)
 			expect(text).toBe("/mode test")
 		})
 
+		it("should replace partial argument with full suggestion", () => {
+			// Bug fix: Type '/model info gpt' with suggestion 'openai/gpt-5'
+			// This test verifies the fix where Tab was incorrectly appending instead of replacing
+			const input = "/model info gpt"
+			for (const char of input) {
+				const key: Key = {
+					name: char,
+					sequence: char,
+					ctrl: false,
+					meta: false,
+					shift: false,
+					paste: false,
+				}
+				store.set(keyboardHandlerAtom, key)
+			}
+
+			// Set up argument suggestions
+			const mockArgumentSuggestion: ArgumentSuggestion = {
+				value: "openai/gpt-5",
+				description: "OpenAI GPT-5 model",
+				matchScore: 90,
+				highlightedValue: "openai/gpt-5",
+			}
+			store.set(argumentSuggestionsAtom, [mockArgumentSuggestion])
+			store.set(suggestionsAtom, []) // No command suggestions
+			store.set(selectedIndexAtom, 0)
+
+			// Press Tab
+			const tabKey: Key = {
+				name: "tab",
+				sequence: "\t",
+				ctrl: false,
+				meta: false,
+				shift: false,
+				paste: false,
+			}
+			store.set(keyboardHandlerAtom, tabKey)
+
+			// Should replace 'gpt' with 'openai/gpt-5' (not append to get 'gptopenai/gpt-5')
+			const text = store.get(textBufferStringAtom)
+			expect(text).toBe("/model info openai/gpt-5")
+		})
+
+		it("should complete argument from empty with trailing space", () => {
+			// Type '/model info ' (with trailing space)
+			const input = "/model info "
+			for (const char of input) {
+				const key: Key = {
+					name: char,
+					sequence: char,
+					ctrl: false,
+					meta: false,
+					shift: false,
+					paste: false,
+				}
+				store.set(keyboardHandlerAtom, key)
+			}
+
+			// Set up argument suggestions
+			const mockArgumentSuggestion: ArgumentSuggestion = {
+				value: "openai/gpt-4",
+				description: "OpenAI GPT-4 model",
+				matchScore: 100,
+				highlightedValue: "openai/gpt-4",
+			}
+			store.set(argumentSuggestionsAtom, [mockArgumentSuggestion])
+			store.set(suggestionsAtom, [])
+			store.set(selectedIndexAtom, 0)
+
+			// Press Tab
+			const tabKey: Key = {
+				name: "tab",
+				sequence: "\t",
+				ctrl: false,
+				meta: false,
+				shift: false,
+				paste: false,
+			}
+			store.set(keyboardHandlerAtom, tabKey)
+
+			// Should add the full suggestion value
+			const text = store.get(textBufferStringAtom)
+			expect(text).toBe("/model info openai/gpt-4")
+		})
+
 		it("should handle exact match completion", () => {
 			// Type '/help' - this will automatically trigger autocomplete
 			const input = "/help"

cli/src/state/atoms/keyboard.ts

@@ -487,11 +487,17 @@ function handleAutocompleteKeys(get: any, set: any, key: Key): void {
 				const suggestion = allSuggestions[selectedIndex]
 				const currentText = get(textBufferStringAtom)
 
-				// Get only the missing part to append
-				const completionText = getCompletionText(currentText, suggestion)
-
-				// Insert the completion text
-				set(insertTextAtom, completionText)
+				// For argument suggestions, replace the entire input with formatted suggestion
+				// For command suggestions, append the completion text
+				if ("command" in suggestion) {
+					// CommandSuggestion - append only the missing part
+					const completionText = getCompletionText(currentText, suggestion)
+					set(insertTextAtom, completionText)
+				} else {
+					// ArgumentSuggestion - replace entire input to avoid duplication
+					const newText = formatSuggestion(suggestion, currentText)
+					set(setTextAtom, newText)
+				}
 			}
 			return