feat(coding-agent,tui): add stacked autocomplete providers closes #2983

packages/coding-agent/src/core/extensions/index.ts

@@ -29,6 +29,7 @@ export type {
 	AppendEntryHandler,
 	// App keybindings (for custom editors)
 	AppKeybinding,
+	AutocompleteProviderFactory,
 	// Events - Tool (ToolCallEvent types)
 	BashToolCallEvent,
 	BashToolResultEvent,

packages/coding-agent/src/core/extensions/runner.ts

@@ -204,6 +204,7 @@ const noOpUIContext: ExtensionUIContext = {
 	setEditorText: () => {},
 	getEditorText: () => "",
 	editor: async () => undefined,
+	addAutocompleteProvider: () => {},
 	setEditorComponent: () => {},
 	get theme() {
 		return theme;

packages/coding-agent/src/core/extensions/types.ts

@@ -30,6 +30,7 @@ import type {
 } from "@mariozechner/pi-ai";
 import type {
 	AutocompleteItem,
+	AutocompleteProvider,
 	Component,
 	EditorComponent,
 	EditorTheme,
@@ -112,6 +113,9 @@ export interface WorkingIndicatorOptions {
 	intervalMs?: number;
 }
 
+/** Wrap the current autocomplete provider with additional behavior. */
+export type AutocompleteProviderFactory = (current: AutocompleteProvider) => AutocompleteProvider;
+
 /**
  * UI context for extensions to request interactive UI.
  * Each mode (interactive, RPC, print) provides its own implementation.
@@ -206,6 +210,9 @@ export interface ExtensionUIContext {
 	/** Show a multi-line editor for text editing. */
 	editor(title: string, prefill?: string): Promise<string | undefined>;
 
+	/** Stack additional autocomplete behavior on top of the built-in provider. */
+	addAutocompleteProvider(factory: AutocompleteProviderFactory): void;
+
 	/**
 	 * Set a custom editor component via factory function.
 	 * Pass undefined to restore the default editor.