MCP Client / API Access Question (Atlassian + Playwright + Custom MCP)

[surekharapuru123]

Pre-submission Checklist

• I have checked that this question would not be more appropriate as an issue in a specific repository
• I have searched existing discussions and documentation for answers

Question Category

• Protocol Specification
• SDK Usage
• Server Implementation
• General Implementation
• Documentation
• Other

Your Question

Hi MCP community 👋

I’m currently using multiple MCP servers:

Atlassian MCP (Jira)

Playwright MCP

A custom MCP server for automation flows

These are working correctly when run via STDIO (for example from VS Code using MCP config).

🎯 What I’m trying to achieve

I want to access these MCP servers from my own chat agent via an API, so that:

My chat agent receives a user prompt

The agent calls MCP tools (Playwright / Jira / custom MCP)

The results are returned back to the chat agent over HTTP

Essentially, I’m trying to build an API bridge between my chat agent and MCP servers.

🚫 Problem I’m facing

When I try to use client or WebSocket-related modules from the MCP SDK, I get errors like:

Error: Cannot find module '.../dist/esm/index.js'

or similar issues when attempting imports related to:

WebSocket clients

MCP client SDK usage outside VS Code

This made me unsure whether:

MCP officially supports HTTP / WebSocket access

There is a supported client SDK for external agents

Or if MCP is STDIO-only by design

❓ Questions for the community

Is MCP intentionally STDIO-only, with no official WebSocket or HTTP interface?

Is there a recommended pattern to expose MCP tools to an external chat agent (e.g., via a custom HTTP bridge)?

Is there a supported client API in @modelcontextprotocol/sdk, or should we avoid importing client modules entirely?

Are there any reference implementations or best practices for running MCP servers outside VS Code?

✅ What I’m looking for

Confirmation of the correct architecture

Guidance on whether building an MCP → HTTP bridge is the intended approach

Any official docs, examples, or recommendations

Thanks in advance 🙏
This project is super promising, and I’d love to align with MCP’s intended usage patterns.

[Dumbris]

MCP officially supports HTTP access - but not WebSockets (yet).

The https://modelcontextprotocol.io/specification/2025-03-26/basic/transports defines two standard transports:

1. stdio - client launches server as subprocess
2. Streamable HTTP - HTTP POST/GET with optional SSE streaming (replaces the deprecated HTTP+SSE transport)

You can use the MCP SDK client to connect to any MCP server, then bridge calls via your own REST API. However, MCP is stateful - it uses session IDs (Mcp-Session-Id header) for context retention across interactions. You'll need to map your web chat user sessions to MCP sessions. If your web chat is backed by an LLM, consider using an existing agent framework that already handles this complexity:
e.g.
https://google.github.io/adk-docs/mcp/ has built-in MCP client (McpToolset) and provides
https://google.github.io/adk-docs/api-reference/rest/ with user_id + session_id management

[surekharapuru123]

I am getting this error while use sdk client S C:\Surekha\MCP Projects\agent-mcp-api> node src/server.js
node:internal/modules/esm/resolve:274
throw new ERR_MODULE_NOT_FOUND(
^

Error [ERR_MODULE_NOT_FOUND]: Cannot find module 'C:\Surekha\MCP Projects\agent-mcp-api\node_modules@modelcontextprotocol\sdk\dist\esm\index.js' imported from C:\Surekha\MCP Projects\agent-mcp-api\src\mcp\index.js
at finalizeResolution (node:internal/modules/esm/resolve:274:11)
at moduleResolve (node:internal/modules/esm/resolve:859:10)
at defaultResolve (node:internal/modules/esm/resolve:983:11)
at ModuleLoader.defaultResolve (node:internal/modules/esm/loader:801:12)
at #cachedDefaultResolve (node:internal/modules/esm/loader:725:25)
at ModuleLoader.resolve (node:internal/modules/esm/loader:708:38)
at ModuleLoader.getModuleJobForImport (node:internal/modules/esm/loader:309:38)
at onImport.tracePromise.proto (node:internal/modules/esm/loader:659:36)
at TracingChannel.tracePromise (node:diagnostics_channel:344:14)
at ModuleLoader.import (node:internal/modules/esm/loader:658:21) {
code: 'ERR_MODULE_NOT_FOUND',
url: 'file:///C:/Surekha/MCP%20Projects/agent-mcp-api/node_modules/@modelcontextprotocol/sdk/dist/esm/index.js'
}
please check