add check for mcp mode

Author: pelikhan

packages/cli/src/mcpserver.ts

@@ -11,6 +11,7 @@ import { errorMessage } from "../../core/src/error"
 import { setConsoleColors } from "../../core/src/consolecolor"
 import { startProjectWatcher } from "./watch"
 import { applyRemoteOptions, RemoteOptions } from "./remote"
+import { setMcpMode } from "../../core/src/mcp"
 
 /**
  * Starts the MCP server.
@@ -26,6 +27,7 @@ export async function startMcpServer(
 ) {
     setConsoleColors(false)
     logVerbose(`mcp server: starting...`)
+    setMcpMode("server")
 
     await applyRemoteOptions(options)
 

packages/core/src/mcp.ts

@@ -0,0 +1,13 @@
+import debug from "debug"
+const dbg = debug("genaiscript:mcp")
+export let mcpMode: "server" | "client" = undefined
+
+export function setMcpMode(mode: "server" | "client") {
+    if (mcpMode && mcpMode !== mode) {
+        throw new Error(
+            `MCP mode already set to ${mcpMode}. Cannot change to ${mode}`
+        )
+    }
+    mcpMode = mode
+    dbg(`mode: ${mode}`)
+}

packages/core/src/mcpclient.ts

@@ -12,6 +12,7 @@ import { errorMessage } from "./error"
 import { CancellationOptions, toSignal } from "./cancellation"
 import type { ProgressCallback } from "@modelcontextprotocol/sdk/shared/protocol.js"
 import { deleteUndefinedValues } from "./cleaners"
+import { setMcpMode } from "./mcp"
 
 export class McpClientManager extends EventTarget implements AsyncDisposable {
     readonly options: TraceOptions
@@ -31,6 +32,7 @@ export class McpClientManager extends EventTarget implements AsyncDisposable {
         dbgc(`starting ${id}`)
         const trace = this.options.trace.startTraceDetails(`🪚 mcp ${id}`)
         try {
+            setMcpMode("client")
             const { Client } = await import(
                 "@modelcontextprotocol/sdk/client/index.js"
             )