feat: add scratchpad chat sessions

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

sidecar/src/Kopaya.AgentHost/Contracts/ProtocolModels.cs

@@ -71,6 +71,7 @@ public sealed class RunTurnCommandDto : SidecarCommandEnvelope
 {
     public string SessionId { get; init; } = string.Empty;
     public string ProjectPath { get; init; } = string.Empty;
+    public string WorkspaceKind { get; init; } = "project";
     public PatternDefinitionDto Pattern { get; init; } = new();
     public IReadOnlyList<ChatMessageDto> Messages { get; init; } = [];
 }

sidecar/src/Kopaya.AgentHost/Services/AgentInstructionComposer.cs

@@ -7,12 +7,22 @@ internal static class AgentInstructionComposer
     public static string Compose(
         PatternDefinitionDto pattern,
         PatternAgentDefinitionDto agent,
-        int agentIndex)
+        int agentIndex,
+        string workspaceKind = "project")
     {
         string baseInstructions = agent.Instructions.Trim();
+        string workspaceGuidance = string.Equals(workspaceKind, "scratchpad", StringComparison.OrdinalIgnoreCase)
+            ? """
+              You are operating in scratchpad mode.
+              Treat this session as pure ad-hoc Q&A rather than repository automation.
+              Do not inspect, modify, create, or delete files, and do not behave as though you are working inside a user project.
+              Answer conversationally and focus on the user's question directly.
+              """
+            : string.Empty;
+
         if (!string.Equals(pattern.Mode, "handoff", StringComparison.OrdinalIgnoreCase))
         {
-            return baseInstructions;
+            return JoinInstructionBlocks(baseInstructions, workspaceGuidance);
         }
 
         string runtimeGuidance = agentIndex == 0
@@ -28,8 +38,13 @@ internal static class AgentInstructionComposer
               Do not push the actual work back to triage unless you are blocked or the request is clearly outside your specialty.
               """;
 
-        return string.IsNullOrWhiteSpace(baseInstructions)
+        return JoinInstructionBlocks(baseInstructions, workspaceGuidance, runtimeGuidance);
-            ? runtimeGuidance
+    }
-            : $"{baseInstructions}\n\n{runtimeGuidance}";
+
+    private static string JoinInstructionBlocks(params string[] blocks)
+    {
+        return string.Join(
+            "\n\n",
+            blocks.Where(block => !string.IsNullOrWhiteSpace(block)).Select(block => block.Trim()));
     }
 }

sidecar/src/Kopaya.AgentHost/Services/CopilotWorkflowRunner.cs

@@ -40,7 +40,7 @@ public sealed class CopilotWorkflowRunner : ITurnWorkflowRunner
             throw new InvalidOperationException(validationError.Message);
         }
 
-        await using AgentBundle bundle = await AgentBundle.CreateAsync(command.Pattern, command.ProjectPath, cancellationToken);
+        await using AgentBundle bundle = await AgentBundle.CreateAsync(command, cancellationToken);
         Workflow workflow = bundle.BuildWorkflow(command.Pattern);
         List<ChatMessage> inputMessages = command.Messages.Select(ToChatMessage).ToList();
 
@@ -436,15 +436,15 @@ public sealed class CopilotWorkflowRunner : ITurnWorkflowRunner
         public IReadOnlyList<AIAgent> Agents { get; }
 
         public static async Task<AgentBundle> CreateAsync(
-            PatternDefinitionDto pattern,
+            RunTurnCommandDto command,
-            string projectPath,
             CancellationToken cancellationToken)
         {
             List<IAsyncDisposable> disposables = [];
             List<AIAgent> agents = [];
             CopilotClientOptions clientOptions = CopilotCliPathResolver.CreateClientOptions();
+            bool isScratchpad = string.Equals(command.WorkspaceKind, "scratchpad", StringComparison.OrdinalIgnoreCase);
 
-            foreach ((PatternAgentDefinitionDto definition, int agentIndex) in pattern.Agents.Select((definition, index) => (definition, index)))
+            foreach ((PatternAgentDefinitionDto definition, int agentIndex) in command.Pattern.Agents.Select((definition, index) => (definition, index)))
             {
                 CopilotClient client = new(clientOptions);
                 await client.StartAsync(cancellationToken).ConfigureAwait(false);
@@ -455,13 +455,18 @@ public sealed class CopilotWorkflowRunner : ITurnWorkflowRunner
                     ReasoningEffort = definition.ReasoningEffort,
                     SystemMessage = new SystemMessageConfig
                     {
-                        Content = AgentInstructionComposer.Compose(pattern, definition, agentIndex),
+                        Content = AgentInstructionComposer.Compose(command.Pattern, definition, agentIndex, command.WorkspaceKind),
                     },
-                    WorkingDirectory = projectPath,
+                    WorkingDirectory = command.ProjectPath,
                     OnPermissionRequest = ApprovePermissionAsync,
                     Streaming = true,
                 };
 
+                if (isScratchpad)
+                {
+                    sessionConfig.AvailableTools = [];
+                }
+
                 GitHubCopilotAgent agent = new(
                     client,
                     sessionConfig,

sidecar/tests/Kopaya.AgentHost.Tests/AgentInstructionComposerTests.cs

@@ -67,6 +67,32 @@ public sealed class AgentInstructionComposerTests
         Assert.Contains("own the substantive answer", instructions, StringComparison.OrdinalIgnoreCase);
     }
 
+    [Fact]
+    public void Compose_AddsScratchpadGuidanceForProjectlessQaSessions()
+    {
+        PatternDefinitionDto pattern = new()
+        {
+            Id = "pattern-single",
+            Name = "Single",
+            Mode = "single",
+            Availability = "available",
+        };
+        PatternAgentDefinitionDto agent = CreateAgent(
+            id: "agent-primary",
+            name: "Primary Agent",
+            instructions: "You are a helpful assistant.");
+
+        string instructions = AgentInstructionComposer.Compose(
+            pattern,
+            agent,
+            agentIndex: 0,
+            workspaceKind: "scratchpad");
+
+        Assert.Contains("scratchpad mode", instructions, StringComparison.OrdinalIgnoreCase);
+        Assert.Contains("pure ad-hoc Q&A", instructions, StringComparison.OrdinalIgnoreCase);
+        Assert.Contains("Do not inspect, modify, create, or delete files", instructions, StringComparison.OrdinalIgnoreCase);
+    }
+
     private static PatternAgentDefinitionDto CreateAgent(string id, string name, string instructions)
     {
         return new PatternAgentDefinitionDto

src/main/KopayaAppService.ts

@@ -5,7 +5,7 @@ import { dialog } from 'electron';
 
 import type { AgentActivityEvent, TurnDeltaEvent } from '@shared/contracts/sidecar';
 import { buildSessionTitle, validatePatternDefinition, type PatternDefinition } from '@shared/domain/pattern';
-import type { ProjectRecord } from '@shared/domain/project';
+import { isScratchpadProject, type ProjectRecord } from '@shared/domain/project';
 import type { SessionEventRecord } from '@shared/domain/event';
 import type { ChatMessageRecord, SessionRecord } from '@shared/domain/session';
 import type { WorkspaceState } from '@shared/domain/workspace';
@@ -75,6 +75,10 @@ export class KopayaAppService extends EventEmitter<AppServiceEvents> {
   }
 
   async removeProject(projectId: string): Promise<WorkspaceState> {
+    if (isScratchpadProject(projectId)) {
+      throw new Error('Scratchpad cannot be removed.');
+    }
+
     const workspace = await this.loadWorkspace();
     workspace.projects = workspace.projects.filter((project) => project.id !== projectId);
     workspace.sessions = workspace.sessions.filter((session) => session.projectId !== projectId);
@@ -187,6 +191,7 @@ export class KopayaAppService extends EventEmitter<AppServiceEvents> {
     });
 
     const requestId = createId('turn');
+    const workspaceKind = isScratchpadProject(project) ? 'scratchpad' : 'project';
     try {
       const responseMessages = await this.sidecar.runTurn(
         {
@@ -194,6 +199,7 @@ export class KopayaAppService extends EventEmitter<AppServiceEvents> {
           requestId,
           sessionId: session.id,
           projectPath: project.path,
+          workspaceKind,
           pattern,
           messages: session.messages,
         },

src/main/persistence/appPaths.ts

@@ -4,3 +4,7 @@ import { join } from 'node:path';
 export function getWorkspaceFilePath(): string {
   return join(app.getPath('userData'), 'workspace.json');
 }
+
+export function getScratchpadDirectoryPath(): string {
+  return join(app.getPath('userData'), 'scratchpad');
+}

src/main/persistence/workspaceRepository.ts

@@ -1,9 +1,12 @@
+import { mkdir } from 'node:fs/promises';
+
 import { createBuiltinPatterns } from '@shared/domain/pattern';
 import type { PatternDefinition } from '@shared/domain/pattern';
+import { mergeScratchpadProject } from '@shared/domain/project';
 import { createWorkspaceSeed, type WorkspaceState } from '@shared/domain/workspace';
 import { nowIso } from '@shared/utils/ids';
 
-import { getWorkspaceFilePath } from '@main/persistence/appPaths';
+import { getScratchpadDirectoryPath, getWorkspaceFilePath } from '@main/persistence/appPaths';
 import { readJsonFile, writeJsonFile } from '@main/persistence/jsonStore';
 
 function mergePatterns(existingPatterns: PatternDefinition[]): PatternDefinition[] {
@@ -32,20 +35,34 @@ function mergePatterns(existingPatterns: PatternDefinition[]): PatternDefinition
 
 export class WorkspaceRepository {
   readonly filePath = getWorkspaceFilePath();
+  readonly scratchpadPath = getScratchpadDirectoryPath();
 
   async load(): Promise<WorkspaceState> {
+    await mkdir(this.scratchpadPath, { recursive: true });
+
     const stored = await readJsonFile<WorkspaceState>(this.filePath);
     if (!stored) {
-      const seeded = createWorkspaceSeed();
+      const seededBase = createWorkspaceSeed();
+      const projects = mergeScratchpadProject([], this.scratchpadPath);
+      const seeded: WorkspaceState = {
+        ...seededBase,
+        projects,
+        selectedProjectId: projects[0]?.id,
+      };
       await this.save(seeded);
       return seeded;
     }
 
+    const projects = mergeScratchpadProject(stored.projects ?? [], this.scratchpadPath);
+
     const workspace: WorkspaceState = {
       ...stored,
       patterns: mergePatterns(stored.patterns ?? []),
-      projects: stored.projects ?? [],
+      projects,
       sessions: stored.sessions ?? [],
+      selectedProjectId: projects.some((project) => project.id === stored.selectedProjectId)
+        ? stored.selectedProjectId
+        : projects[0]?.id,
       lastUpdatedAt: stored.lastUpdatedAt ?? nowIso(),
     };
 

src/renderer/App.tsx

@@ -15,6 +15,7 @@ import { applySessionEventWorkspace } from '@renderer/lib/sessionWorkspace';
 import { WelcomePane } from '@renderer/components/WelcomePane';
 import { getElectronApi } from '@renderer/lib/electronApi';
 import type { PatternDefinition } from '@shared/domain/pattern';
+import { isScratchpadProject } from '@shared/domain/project';
 import type { WorkspaceState } from '@shared/domain/workspace';
 import { createId, nowIso } from '@shared/utils/ids';
 
@@ -106,6 +107,10 @@ export default function App() {
     () => (selectedSession ? sessionActivities[selectedSession.id] : undefined),
     [selectedSession, sessionActivities],
   );
+  const hasUserProjects = useMemo(
+    () => (workspace?.projects.some((project) => !isScratchpadProject(project)) ?? false),
+    [workspace?.projects],
+  );
 
   // Loading state
   if (!workspace) {
@@ -147,7 +152,7 @@ export default function App() {
   } else {
     content = (
       <WelcomePane
-        hasProjects={workspace.projects.length > 0}
+        hasProjects={hasUserProjects}
         onAddProject={() => void api.addProject()}
         onNewSession={() => setShowNewSession(true)}
         onOpenSettings={() => setShowSettings(true)}

src/renderer/components/ChatPane.tsx

@@ -5,7 +5,7 @@ import { MarkdownContent } from '@renderer/components/MarkdownContent';
 import { getAssistantMessagePhase } from '@renderer/lib/messagePhase';
 
 import type { PatternDefinition } from '@shared/domain/pattern';
-import type { ProjectRecord } from '@shared/domain/project';
+import { isScratchpadProject, type ProjectRecord } from '@shared/domain/project';
 import type { SessionRecord } from '@shared/domain/session';
 
 function ThinkingDots() {
@@ -31,6 +31,7 @@ export function ChatPane({ project, pattern, session, onSend }: ChatPaneProps) {
   const textareaRef = useRef<HTMLTextAreaElement>(null);
 
   const isBusy = session.status === 'running';
+  const isScratchpad = isScratchpadProject(project);
 
   useEffect(() => {
     transcriptRef.current?.scrollTo({
@@ -60,7 +61,7 @@ export function ChatPane({ project, pattern, session, onSend }: ChatPaneProps) {
         <div className="min-w-0">
           <h2 className="truncate text-sm font-semibold text-zinc-100">{session.title}</h2>
           <p className="mt-0.5 truncate text-[12px] text-zinc-500">
-            {project.name} · {pattern.name} · {pattern.mode}
+            {isScratchpad ? `Scratchpad · ${pattern.name}` : `${project.name} · ${pattern.name} · ${pattern.mode}`}
           </p>
         </div>
         <div className="flex items-center gap-2">
@@ -90,8 +91,17 @@ export function ChatPane({ project, pattern, session, onSend }: ChatPaneProps) {
               Send a message to start the conversation
             </p>
             <p className="text-[12px] text-zinc-700">
-              Using <span className="text-zinc-500">{pattern.name}</span> in{' '}
+              {isScratchpad ? (
-              <span className="text-zinc-500">{project.name}</span>
+                <>
+                  Scratchpad is ready for ad-hoc questions using{' '}
+                  <span className="text-zinc-500">{pattern.name}</span>
+                </>
+              ) : (
+                <>
+                  Using <span className="text-zinc-500">{pattern.name}</span> in{' '}
+                  <span className="text-zinc-500">{project.name}</span>
+                </>
+              )}
             </p>
           </div>
         ) : (

src/renderer/components/NewSessionModal.tsx

@@ -1,8 +1,8 @@
-import { useState } from 'react';
+import { useEffect, useMemo, useState } from 'react';
 import { X } from 'lucide-react';
 
 import type { PatternDefinition } from '@shared/domain/pattern';
-import type { ProjectRecord } from '@shared/domain/project';
+import { isScratchpadProject, type ProjectRecord } from '@shared/domain/project';
 
 interface NewSessionModalProps {
   projects: ProjectRecord[];
@@ -19,10 +19,24 @@ export function NewSessionModal({
   onClose,
   onCreate,
 }: NewSessionModalProps) {
-  const availablePatterns = patterns.filter((p) => p.availability !== 'unavailable');
   const [projectId, setProjectId] = useState(defaultProjectId ?? projects[0]?.id ?? '');
+  const availablePatterns = useMemo(
+    () =>
+      patterns.filter(
+        (pattern) =>
+          pattern.availability !== 'unavailable'
+          && (!isScratchpadProject(projectId) || pattern.mode === 'single'),
+      ),
+    [patterns, projectId],
+  );
   const [patternId, setPatternId] = useState(availablePatterns[0]?.id ?? '');
 
+  useEffect(() => {
+    if (!availablePatterns.some((pattern) => pattern.id === patternId)) {
+      setPatternId(availablePatterns[0]?.id ?? '');
+    }
+  }, [availablePatterns, patternId]);
+
   const canCreate = projectId && patternId;
 
   return (
@@ -55,6 +69,12 @@ export function NewSessionModal({
                 </option>
               ))}
             </select>
+            {isScratchpadProject(projectId) && (
+              <p className="text-[12px] leading-relaxed text-zinc-600">
+                Scratchpad is a projectless 1-on-1 chat for ad-hoc questions. It should behave like
+                pure Q&A rather than repo automation.
+              </p>
+            )}
           </label>
 
           <label className="block space-y-1.5">
@@ -75,6 +95,11 @@ export function NewSessionModal({
                 {availablePatterns.find((p) => p.id === patternId)?.description}
               </p>
             )}
+            {isScratchpadProject(projectId) && (
+              <p className="text-[12px] leading-relaxed text-zinc-700">
+                Scratchpad supports single-agent chat patterns only.
+              </p>
+            )}
           </label>
         </div>
 

src/renderer/components/Sidebar.tsx

@@ -16,7 +16,7 @@ import {
 } from 'lucide-react';
 
 import type { OrchestrationMode, PatternDefinition } from '@shared/domain/pattern';
-import type { ProjectRecord } from '@shared/domain/project';
+import { isScratchpadProject, type ProjectRecord } from '@shared/domain/project';
 import type { SessionRecord } from '@shared/domain/session';
 import type { WorkspaceState } from '@shared/domain/workspace';
 
@@ -161,6 +161,7 @@ function ProjectGroup({
   onSessionSelect: (sessionId: string) => void;
 }) {
   const [expanded, setExpanded] = useState(true);
+  const isScratchpad = isScratchpadProject(project);
 
   const patternMap = useMemo(() => {
     const map = new Map<string, PatternDefinition>();
@@ -182,7 +183,11 @@ function ProjectGroup({
         ) : (
           <ChevronRight className="size-3 shrink-0 text-zinc-500" />
         )}
-        <FolderOpen className="size-3.5 shrink-0 text-zinc-500 transition group-hover:text-indigo-400" />
+        {isScratchpad ? (
+          <MessageSquare className="size-3.5 shrink-0 text-zinc-500 transition group-hover:text-indigo-400" />
+        ) : (
+          <FolderOpen className="size-3.5 shrink-0 text-zinc-500 transition group-hover:text-indigo-400" />
+        )}
         <span className="truncate">{project.name}</span>
 
         <div className="ml-auto flex items-center gap-1.5">
@@ -202,7 +207,7 @@ function ProjectGroup({
         <div className="ml-2 mt-0.5 space-y-0.5 border-l border-zinc-800/60 pl-2">
           {sessions.length === 0 ? (
             <div className="px-3 py-3 text-center text-[12px] text-zinc-600">
-              No sessions yet
+              {isScratchpad ? 'No scratchpad chats yet' : 'No sessions yet'}
             </div>
           ) : (
             sessions.map((session) => (
@@ -231,6 +236,9 @@ export function Sidebar({
   onSessionSelect,
   onOpenSettings,
 }: SidebarProps) {
+  const scratchpadProject = workspace.projects.find((project) => isScratchpadProject(project));
+  const userProjects = workspace.projects.filter((project) => !isScratchpadProject(project));
+
   return (
     <div className="flex h-full flex-col">
       {/* Header — extra top padding clears the title bar overlay zone */}
@@ -272,48 +280,69 @@ export function Sidebar({
 
       {/* Project + Session Tree */}
       <div className="flex-1 overflow-y-auto px-2 py-2">
-        {workspace.projects.length === 0 ? (
+        <div className="space-y-3">
-          <div className="flex flex-col items-center gap-4 px-4 py-10 text-center">
+          {scratchpadProject && (
-            <div className="relative">
+            <div className="space-y-1">
-              <div className="flex size-14 items-center justify-center rounded-2xl bg-zinc-800/50 ring-1 ring-zinc-700/50">
+              <div className="px-2 text-[10px] font-semibold uppercase tracking-[0.12em] text-zinc-600">
-                <FolderOpen className="size-7 text-zinc-600" />
+                Scratchpad
               </div>
-              <div className="absolute -bottom-1 -right-1 flex size-6 items-center justify-center rounded-full bg-indigo-600 ring-2 ring-[var(--color-surface-1)]">
-                <Plus className="size-3 text-white" />
-              </div>
-            </div>
-            <div>
-              <p className="text-[13px] font-medium text-zinc-300">No projects yet</p>
-              <p className="mt-1 text-[12px] leading-relaxed text-zinc-500">
-                Add a project folder to start<br />orchestrating AI agents
-              </p>
-            </div>
-            <button
-              className="rounded-lg bg-indigo-600 px-4 py-2 text-[13px] font-medium text-white transition hover:bg-indigo-500"
-              onClick={onAddProject}
-              type="button"
-            >
-              Add Project
-            </button>
-          </div>
-        ) : (
-          <div className="space-y-1">
-            {workspace.projects.map((project) => (
               <ProjectGroup
-                key={project.id}
+                key={scratchpadProject.id}
                 onSessionSelect={onSessionSelect}
                 patterns={workspace.patterns}
-                project={project}
+                project={scratchpadProject}
                 selectedSessionId={workspace.selectedSessionId}
-                sessions={workspace.sessions.filter((s) => s.projectId === project.id)}
+                sessions={workspace.sessions.filter((session) => session.projectId === scratchpadProject.id)}
               />
-            ))}
+            </div>
-          </div>
+          )}
-        )}
+
+          {userProjects.length === 0 ? (
+            <div className="flex flex-col items-center gap-4 px-4 py-8 text-center">
+              <div className="relative">
+                <div className="flex size-14 items-center justify-center rounded-2xl bg-zinc-800/50 ring-1 ring-zinc-700/50">
+                  <FolderOpen className="size-7 text-zinc-600" />
+                </div>
+                <div className="absolute -bottom-1 -right-1 flex size-6 items-center justify-center rounded-full bg-indigo-600 ring-2 ring-[var(--color-surface-1)]">
+                  <Plus className="size-3 text-white" />
+                </div>
+              </div>
+              <div>
+                <p className="text-[13px] font-medium text-zinc-300">No projects yet</p>
+                <p className="mt-1 text-[12px] leading-relaxed text-zinc-500">
+                  Use Scratchpad for ad-hoc chat or add a repo<br />to work against project files
+                </p>
+              </div>
+              <button
+                className="rounded-lg bg-indigo-600 px-4 py-2 text-[13px] font-medium text-white transition hover:bg-indigo-500"
+                onClick={onAddProject}
+                type="button"
+              >
+                Add Project
+              </button>
+            </div>
+          ) : (
+            <div className="space-y-1">
+              <div className="px-2 text-[10px] font-semibold uppercase tracking-[0.12em] text-zinc-600">
+                Projects
+              </div>
+              {userProjects.map((project) => (
+                <ProjectGroup
+                  key={project.id}
+                  onSessionSelect={onSessionSelect}
+                  patterns={workspace.patterns}
+                  project={project}
+                  selectedSessionId={workspace.selectedSessionId}
+                  sessions={workspace.sessions.filter((session) => session.projectId === project.id)}
+                />
+              ))}
+            </div>
+          )}
+        </div>
       </div>
 
       {/* Footer */}
-      {workspace.projects.length > 0 && (
+      {userProjects.length > 0 && (
         <div className="border-t border-[var(--color-border)] px-3 py-2">
           <button
             className="flex w-full items-center gap-2 rounded-lg px-2 py-1.5 text-[12px] text-zinc-500 transition hover:bg-zinc-800/60 hover:text-zinc-300"

src/renderer/components/WelcomePane.tsx

@@ -23,28 +23,27 @@ export function WelcomePane({
         <div>
           <h1 className="text-xl font-semibold text-zinc-100">Welcome to kopaya</h1>
           <p className="mt-2 max-w-md text-sm leading-relaxed text-zinc-500">
-            Orchestrate AI agents across your projects. Start a session to begin a conversation
+            Start a scratchpad conversation for ad-hoc questions or connect a project to work with
-            with one or more Copilot-backed agents.
+            repo-aware Copilot agents.
           </p>
         </div>
 
         <div className="flex flex-col items-center gap-2">
-          {hasProjects ? (
+          <button
+            className="flex items-center gap-2 rounded-lg bg-indigo-600 px-5 py-2.5 text-sm font-medium text-white transition hover:bg-indigo-500"
+            onClick={onNewSession}
+            type="button"
+          >
+            <Plus className="size-4" />
+            New Session
+          </button>
+          {!hasProjects && (
             <button
-              className="flex items-center gap-2 rounded-lg bg-indigo-600 px-5 py-2.5 text-sm font-medium text-white transition hover:bg-indigo-500"
+              className="flex items-center gap-2 rounded-lg px-4 py-2 text-sm text-zinc-500 transition hover:bg-zinc-900 hover:text-zinc-300"
-              onClick={onNewSession}
-              type="button"
-            >
-              <Plus className="size-4" />
-              New Session
-            </button>
-          ) : (
-            <button
-              className="flex items-center gap-2 rounded-lg bg-indigo-600 px-5 py-2.5 text-sm font-medium text-white transition hover:bg-indigo-500"
               onClick={onAddProject}
               type="button"
             >
-              <Plus className="size-4" />
+              <Plus className="size-3.5" />
               Add Your First Project
             </button>
           )}

src/shared/contracts/sidecar.ts

@@ -27,6 +27,7 @@ export interface RunTurnCommand {
   requestId: string;
   sessionId: string;
   projectPath: string;
+  workspaceKind?: 'project' | 'scratchpad';
   pattern: PatternDefinition;
   messages: ChatMessageRecord[];
 }

src/shared/domain/project.ts

@@ -1,6 +1,44 @@
+import { nowIso } from '@shared/utils/ids';
+
 export interface ProjectRecord {
   id: string;
   name: string;
   path: string;
   addedAt: string;
 }
+
+export const SCRATCHPAD_PROJECT_ID = 'project-scratchpad';
+export const SCRATCHPAD_PROJECT_NAME = 'Scratchpad';
+
+export function createScratchpadProject(path: string, addedAt = nowIso()): ProjectRecord {
+  return {
+    id: SCRATCHPAD_PROJECT_ID,
+    name: SCRATCHPAD_PROJECT_NAME,
+    path,
+    addedAt,
+  };
+}
+
+export function isScratchpadProject(projectIdOrProject?: string | Pick<ProjectRecord, 'id'>): boolean {
+  if (!projectIdOrProject) {
+    return false;
+  }
+
+  return (
+    (typeof projectIdOrProject === 'string' ? projectIdOrProject : projectIdOrProject.id)
+    === SCRATCHPAD_PROJECT_ID
+  );
+}
+
+export function mergeScratchpadProject(existingProjects: ProjectRecord[], scratchpadPath: string): ProjectRecord[] {
+  const existingScratchpad = existingProjects.find((project) => isScratchpadProject(project));
+  const scratchpadProject = createScratchpadProject(
+    scratchpadPath,
+    existingScratchpad?.addedAt ?? nowIso(),
+  );
+
+  return [
+    scratchpadProject,
+    ...existingProjects.filter((project) => !isScratchpadProject(project.id)),
+  ];
+}

tests/shared/project.test.ts

@@ -0,0 +1,46 @@
+import { describe, expect, test } from 'bun:test';
+
+import {
+  SCRATCHPAD_PROJECT_ID,
+  SCRATCHPAD_PROJECT_NAME,
+  createScratchpadProject,
+  isScratchpadProject,
+  mergeScratchpadProject,
+} from '@shared/domain/project';
+
+describe('scratchpad project helpers', () => {
+  test('creates a stable built-in scratchpad project', () => {
+    const project = createScratchpadProject('C:\\Users\\me\\AppData\\Roaming\\kopaya\\scratchpad');
+
+    expect(project.id).toBe(SCRATCHPAD_PROJECT_ID);
+    expect(project.name).toBe(SCRATCHPAD_PROJECT_NAME);
+    expect(project.path).toContain('scratchpad');
+  });
+
+  test('recognizes scratchpad project ids and records', () => {
+    expect(isScratchpadProject(SCRATCHPAD_PROJECT_ID)).toBe(true);
+    expect(
+      isScratchpadProject({
+        id: SCRATCHPAD_PROJECT_ID,
+      }),
+    ).toBe(true);
+    expect(isScratchpadProject('project-normal')).toBe(false);
+  });
+
+  test('merges scratchpad project ahead of normal user projects and preserves user projects', () => {
+    const merged = mergeScratchpadProject(
+      [
+        {
+          id: 'project-a',
+          name: 'Repo A',
+          path: 'C:\\repo-a',
+          addedAt: '2026-03-23T00:00:00.000Z',
+        },
+      ],
+      'C:\\Users\\me\\AppData\\Roaming\\kopaya\\scratchpad',
+    );
+
+    expect(merged[0].id).toBe(SCRATCHPAD_PROJECT_ID);
+    expect(merged[1].id).toBe('project-a');
+  });
+});