Add OS-aware runtime context for cross-platform shell execution

Detect the runtime platform and default shell at startup, inject
platform context into assistant instructions, and replace hardcoded
/bin/sh with the detected shell in command executors (cli + electron).

Made-with: Cursor

apps/cli/src/application/assistant/instructions.ts

@@ -1,5 +1,8 @@
 import { skillCatalog } from "./skills/index.js";
 import { WorkDir as BASE_DIR } from "../../config/config.js";
+import { getRuntimeContext, getRuntimeContextPrompt } from "./runtime-context.js";
+
+const runtimeContextPrompt = getRuntimeContextPrompt(getRuntimeContext());
 
 export const CopilotInstructions = `You are an intelligent workflow assistant helping users manage their workflows in ${BASE_DIR}. You can also help the user with general tasks.
 
@@ -39,6 +42,8 @@ When a user asks for ANY task that might require external capabilities (web sear
 - Use relative paths (no \${BASE_DIR} prefixes) when running commands or referencing files.
 - Keep user data safe—double-check before editing or deleting important resources.
 
+${runtimeContextPrompt}
+
 ## Workspace access & scope
 - You have full read/write access inside \`${BASE_DIR}\` (this resolves to the user's \`~/.rowboat\` directory). Create folders, files, and agents there using builtin tools or allowed shell commands—don't wait for the user to do it manually.
 - If a user mentions a different root (e.g., \`~/.rowboatx\` or another path), clarify whether they meant the Rowboat workspace and propose the equivalent path you can act on. Only refuse if they explicitly insist on an inaccessible location.

apps/cli/src/application/assistant/runtime-context.ts

@@ -0,0 +1,69 @@
+export type RuntimeShellDialect = 'windows-cmd' | 'posix-sh';
+export type RuntimeOsName = 'Windows' | 'macOS' | 'Linux' | 'Unknown';
+
+export interface RuntimeContext {
+  platform: NodeJS.Platform;
+  osName: RuntimeOsName;
+  shellDialect: RuntimeShellDialect;
+  shellExecutable: string;
+}
+
+export function getExecutionShell(platform: NodeJS.Platform = process.platform): string {
+  return platform === 'win32' ? (process.env.ComSpec || 'cmd.exe') : '/bin/sh';
+}
+
+export function getRuntimeContext(platform: NodeJS.Platform = process.platform): RuntimeContext {
+  if (platform === 'win32') {
+    return {
+      platform,
+      osName: 'Windows',
+      shellDialect: 'windows-cmd',
+      shellExecutable: getExecutionShell(platform),
+    };
+  }
+
+  if (platform === 'darwin') {
+    return {
+      platform,
+      osName: 'macOS',
+      shellDialect: 'posix-sh',
+      shellExecutable: getExecutionShell(platform),
+    };
+  }
+
+  if (platform === 'linux') {
+    return {
+      platform,
+      osName: 'Linux',
+      shellDialect: 'posix-sh',
+      shellExecutable: getExecutionShell(platform),
+    };
+  }
+
+  return {
+    platform,
+    osName: 'Unknown',
+    shellDialect: 'posix-sh',
+    shellExecutable: getExecutionShell(platform),
+  };
+}
+
+export function getRuntimeContextPrompt(runtime: RuntimeContext): string {
+  if (runtime.shellDialect === 'windows-cmd') {
+    return `## Runtime Platform (CRITICAL)
+- Detected platform: **${runtime.platform}**
+- Detected OS: **${runtime.osName}**
+- Shell used by executeCommand: **${runtime.shellExecutable}** (Windows Command Prompt / cmd syntax)
+- Use Windows command syntax for executeCommand (for example: \`dir\`, \`type\`, \`copy\`, \`move\`, \`del\`, \`rmdir\`).
+- Use Windows-style absolute paths when outside workspace (for example: \`C:\\Users\\...\`).
+- Do not assume macOS/Linux command syntax when the runtime is Windows.`;
+  }
+
+  return `## Runtime Platform (CRITICAL)
+- Detected platform: **${runtime.platform}**
+- Detected OS: **${runtime.osName}**
+- Shell used by executeCommand: **${runtime.shellExecutable}** (POSIX sh syntax)
+- Use POSIX command syntax for executeCommand (for example: \`ls\`, \`cat\`, \`cp\`, \`mv\`, \`rm\`).
+- Use POSIX paths when outside workspace (for example: \`~/Desktop\`, \`/Users/.../\` on macOS, \`/home/.../\` on Linux).
+- Do not assume Windows command syntax when the runtime is POSIX.`;
+}

apps/cli/src/application/lib/command-executor.ts

@@ -1,11 +1,13 @@
 import { exec, execSync } from 'child_process';
 import { promisify } from 'util';
 import { getSecurityAllowList, SECURITY_CONFIG_PATH } from '../../config/security.js';
+import { getExecutionShell } from '../assistant/runtime-context.js';
 
 const execPromise = promisify(exec);
 const COMMAND_SPLIT_REGEX = /(?:\|\||&&|;|\||\n)/;
 const ENV_ASSIGNMENT_REGEX = /^[A-Za-z_][A-Za-z0-9_]*=.*/;
 const WRAPPER_COMMANDS = new Set(['sudo', 'env', 'time', 'command']);
+const EXECUTION_SHELL = getExecutionShell();
 
 function sanitizeToken(token: string): string {
   return token.trim().replace(/^['"]+|['"]+$/g, '');
@@ -91,7 +93,7 @@ export async function executeCommand(
       cwd: options?.cwd,
       timeout: options?.timeout,
       maxBuffer: options?.maxBuffer || 1024 * 1024, // default 1MB
-      shell: '/bin/sh', // use sh for cross-platform compatibility
+      shell: EXECUTION_SHELL,
     });
 
     return {
@@ -125,7 +127,7 @@ export function executeCommandSync(
       cwd: options?.cwd,
       timeout: options?.timeout,
       encoding: 'utf-8',
-      shell: '/bin/sh',
+      shell: EXECUTION_SHELL,
     });
 
     return {