fix(pi): expose native skills through $ completion (#1286)

cli/src/pi/runPi.test.ts

@@ -69,7 +69,44 @@ vi.mock('./piTransport', () => ({
     },
 }));
 
-import { runPi } from './runPi';
+import { buildPiCommandInventory, formatPiUserMessage, rewritePiSkillPrompt, runPi } from './runPi';
+
+describe('Pi command namespaces', () => {
+    const commands = [
+        { name: 'session-name', description: 'Rename session', source: 'extension' as const },
+        { name: 'fix-tests', description: 'Fix tests', source: 'prompt' as const },
+        { name: 'skill:brave-search', description: 'Search the web', source: 'skill' as const },
+    ];
+
+    it('exposes native skills through $ and keeps them out of slash completion', () => {
+        expect(buildPiCommandInventory(commands)).toEqual({
+            skills: [
+                { name: 'brave-search', description: 'Search the web' },
+            ],
+            slashCommands: [
+                { name: 'session-name', description: 'Rename session', source: 'plugin' },
+                { name: 'fix-tests', description: 'Fix tests', source: 'user' },
+            ],
+        });
+    });
+
+    it('rewrites HAPI $ skills to Pi native skill commands', () => {
+        expect(rewritePiSkillPrompt('$brave-search latest news', commands))
+            .toBe('/skill:brave-search latest news');
+        expect(rewritePiSkillPrompt('$new-skill now', [])).toBe('/skill:new-skill now');
+        expect(rewritePiSkillPrompt('$PATH', commands)).toBe('$PATH');
+    });
+
+    it('keeps the native skill command first when the message has attachments', () => {
+        expect(formatPiUserMessage('$brave-search', [{
+            id: 'attachment-1',
+            filename: 'query.txt',
+            mimeType: 'text/plain',
+            size: 5,
+            path: '/tmp/query.txt',
+        }], commands)).toBe('/skill:brave-search\n\n@/tmp/query.txt');
+    });
+});
 
 describe('runPi startup', () => {
     beforeEach(() => {

cli/src/pi/runPi.ts

@@ -3,22 +3,72 @@ import { bootstrapExistingSession, bootstrapSession } from '@/agent/sessionFacto
 import { registerKillSessionHandler } from '@/claude/registerKillSessionHandler';
 import { registerLocalHandoffHandler } from '@/agent/localHandoff';
 import { createRunnerLifecycle, createModeChangeHandler, setControlledByUser } from '@/agent/runnerLifecycle';
-import { formatMessageWithAttachments } from '@/utils/attachmentFormatter';
+import { formatAttachmentsForClaude, formatMessageWithAttachments } from '@/utils/attachmentFormatter';
 import { getInvokedCwd } from '@/utils/invokedCwd';
 import { PiTransport } from './piTransport';
 import { PiSession } from './session';
 import { parsePiModels, parsePiCommands, sendPiRpcAndWait, wireTransportEvents } from './loop';
 import { PiThinkingLevelSchema, SetSessionConfigPayloadSchema } from './schemas';
 import type { PiThinkingLevel } from './types';
-import type { SlashCommandsResponse } from '@hapi/protocol/apiTypes';
-import type { ListPiModelsResponse } from '@hapi/protocol/apiTypes';
+import type { ListPiModelsResponse, PiCommandSummary, SlashCommand, SlashCommandsResponse } from '@hapi/protocol/apiTypes';
 import { RPC_METHODS } from '@hapi/protocol/rpcMethods';
+import type { ListSkillsResponse, SkillSummary } from '@/modules/common/skills';
+import type { AttachmentMetadata } from '@/api/types';
 
 // Grace period before force-draining prompts buffered during Pi startup when no
 // get_state response arrives. Comfortably above the 10s Pi RPC timeout so a slow
 // but healthy startup still flips ready via get_state first (issue #1143).
 const PI_READY_FALLBACK_MS = 30_000;
 
+function getPiSkillName(commandName: string): string {
+    return commandName.startsWith('skill:') ? commandName.slice('skill:'.length) : commandName;
+}
+
+export function buildPiCommandInventory(commands: readonly PiCommandSummary[]): {
+    skills: SkillSummary[];
+    slashCommands: SlashCommand[];
+} {
+    const skills: SkillSummary[] = [];
+    const slashCommands: SlashCommand[] = [];
+
+    for (const command of commands) {
+        if (command.source === 'skill') {
+            const name = getPiSkillName(command.name);
+            if (name) skills.push({ name, description: command.description });
+            continue;
+        }
+        slashCommands.push({
+            name: command.name,
+            description: command.description,
+            source: command.source === 'prompt' ? 'user' : 'plugin',
+        });
+    }
+
+    return { skills, slashCommands };
+}
+
+export function rewritePiSkillPrompt(message: string, commands: readonly PiCommandSummary[]): string {
+    const match = /^(\s*)\$([a-z0-9]+(?:-[a-z0-9]+)*)(?=\s|$)/.exec(message);
+    if (!match) return message;
+
+    const command = commands.find(candidate =>
+        candidate.source === 'skill' && getPiSkillName(candidate.name) === match[2]
+    );
+    return `${match[1]}/${command?.name ?? `skill:${match[2]}`}${message.slice(match[0].length)}`;
+}
+
+export function formatPiUserMessage(
+    message: string,
+    attachments: AttachmentMetadata[] | undefined,
+    commands: readonly PiCommandSummary[],
+): string {
+    const skillPrompt = rewritePiSkillPrompt(message, commands);
+    if (skillPrompt === message) return formatMessageWithAttachments(message, attachments);
+
+    const attachmentText = formatAttachmentsForClaude(attachments);
+    return attachmentText ? `${skillPrompt}\n\n${attachmentText}` : skillPrompt;
+}
+
 export async function runPi(opts: {
     startedBy?: 'runner' | 'terminal';
     startingMode?: 'local' | 'remote';
@@ -285,38 +335,45 @@ export async function runPi(opts: {
         }
     );
 
-    // --- Slash commands (Pi skills/commands) ---
+    const getPiCommands = async (): Promise<PiCommandSummary[]> => {
+        if (piSession.cachedPiCommands.length > 0) return piSession.cachedPiCommands;
+        try {
+            const data = await sendPiRpcAndWait(piSession, transport, { type: 'get_commands' });
+            const commands = parsePiCommands(data);
+            if (commands.length > 0) piSession.cachedPiCommands = commands;
+            return commands;
+        } catch {
+            return [];
+        }
+    };
+
+    // --- Pi commands and skills ---
     apiSession.rpcHandlerManager.registerHandler<{ agent?: string }, SlashCommandsResponse>(
         RPC_METHODS.ListSlashCommands,
         async () => {
-            let commands = piSession.cachedPiCommands;
-            if (commands.length === 0) {
-                try {
-                    const data = await sendPiRpcAndWait(piSession, transport, { type: 'get_commands' });
-                    commands = parsePiCommands(data);
-                    if (commands.length > 0) {
-                        piSession.cachedPiCommands = commands;
-                    }
-                } catch {
-                    // Fall through to return empty
-                }
-            }
+            const { slashCommands } = buildPiCommandInventory(await getPiCommands());
             return {
                 success: true,
-                commands: commands.map((cmd) => ({
-                    name: cmd.name,
-                    description: cmd.description,
-                    source: cmd.source === 'skill' ? 'plugin' as const
-                        : cmd.source === 'prompt' ? 'user' as const
-                        : 'plugin' as const,
-                })),
+                commands: slashCommands,
             };
         }
     );
 
+    apiSession.rpcHandlerManager.registerHandler<Record<string, never>, ListSkillsResponse>(
+        RPC_METHODS.ListSkills,
+        async () => {
+            const { skills } = buildPiCommandInventory(await getPiCommands());
+            return { success: true, skills };
+        }
+    );
+
     // --- User message handler ---
     apiSession.onUserMessage((message, localId) => {
-        const formattedText = formatMessageWithAttachments(message.content.text, message.content.attachments);
+        const formattedText = formatPiUserMessage(
+            message.content.text,
+            message.content.attachments,
+            piSession.cachedPiCommands,
+        );
         // Gate the send behind Pi startup readiness. A prompt POSTed immediately
         // after spawn (supported handoff pattern — hapi-ping-peer, intake
         // scripts) would otherwise reach Pi before its initial get_state finishes