feat: add daemon mode for persistent MCP connections

README.md

@@ -271,6 +271,8 @@ The CLI searches for configuration in this order:
 | `MCP_MAX_RETRIES` | Retry attempts for transient errors (0 = disable) | `3` |
 | `MCP_RETRY_DELAY` | Base retry delay (milliseconds) | `1000` |
 | `MCP_STRICT_ENV` | Error on missing `${VAR}` in config | `true` |
+| `MCP_DAEMON_SOCKET` | Daemon socket path | `~/.mcp-cli/daemon.sock` |
+| `MCP_DAEMON_IDLE_MS` | Daemon idle timeout (ms) | `300000` |
 
 ## Using with AI Agents
 
@@ -303,8 +305,12 @@ mcp-cli <server>                     # Show server tools and parameters
 mcp-cli <server>/<tool>              # Get tool JSON schema and descriptions
 mcp-cli <server>/<tool> '<json>'     # Call tool with JSON arguments
 mcp-cli grep "<pattern>"             # Search tools by name (glob pattern)
+mcp-cli daemon start                 # Start persistent connection daemon
+mcp-cli daemon stop                  # Stop daemon
 ```
 
+For stateful MCP servers (browser automation, database sessions), start the daemon first. Connections persist across calls.
+
 **Add `-d` to include tool descriptions** (e.g., `mcp-cli <server> -d`)
 
 Workflow:

SKILL.md

@@ -16,6 +16,7 @@ Access MCP servers through the command line. MCP enables interaction with extern
 | `mcp-cli <server>/<tool>` | Get tool JSON schema |
 | `mcp-cli <server>/<tool> '<json>'` | Call tool with arguments |
 | `mcp-cli grep "<glob>"` | Search tools by name |
+| `mcp-cli daemon start\|stop` | Manage persistent connections (for stateful servers) |
 
 **Add `-d` to include descriptions** (e.g., `mcp-cli filesystem -d`)
 

src/commands/call.ts

@@ -22,6 +22,7 @@ import {
   getServerConfig,
   loadConfig,
 } from '../config.js';
+import { callViaDaemon, isDaemonRunning } from '../daemon.js';
 import {
   ErrorCode,
   formatCliError,
@@ -148,6 +149,36 @@ export async function callCommand(options: CallOptions): Promise<void> {
     process.exit(ErrorCode.CLIENT_ERROR);
   }
 
+  if (await isDaemonRunning()) {
+    debug(`routing call through daemon: ${serverName}/${toolName}`);
+    try {
+      const result = await callViaDaemon(
+        serverName,
+        serverConfig,
+        toolName,
+        args,
+      );
+      if (options.json) {
+        console.log(formatJson(result));
+      } else {
+        console.log(formatToolResult(result));
+      }
+      return;
+    } catch (error) {
+      const errMsg = (error as Error).message;
+      if (errMsg.includes('not found') || errMsg.includes('unknown tool')) {
+        console.error(
+          formatCliError(toolNotFoundError(toolName, serverName, undefined)),
+        );
+      } else {
+        console.error(
+          formatCliError(toolExecutionError(toolName, serverName, errMsg)),
+        );
+      }
+      process.exit(ErrorCode.SERVER_ERROR);
+    }
+  }
+
   let client: Client;
   let close: () => Promise<void> = async () => {}; // Initialize to noop to prevent undefined access