[BUG] HTTP MCP Servers Not Available in Conversation Interface (mcp__server__tool format fails)

Resolved 💬 3 comments Opened Dec 25, 2025 by yapxue Closed Dec 29, 2025

Preflight Checklist

  • [x] I have searched existing issues and this hasn't been reported yet
  • [x] This is a single bug report (please file separate reports for different bugs)
  • [x] I am using the latest version of Claude Code

What's Wrong?

HTTP MCP servers connect successfully via CLI (claude mcp list shows "✓ Connected") but tools are not available in conversation interface using the mcp__server__tool format. STDIO MCP servers work correctly.

Environment:

  • Claude Code Version: 2.0.76 (from server logs)
  • OS: macOS Darwin 23.2.0
  • MCP Protocol Version: 2025-11-25

Steps to Reproduce:

  1. Create HTTP MCP server implementing MCP 2025-11-25 protocol
  2. Add server: claude mcp add --transport http api5io http://localhost:8090/mcp
  3. Verify connection: claude mcp list shows "✓ Connected"
  4. Try to use tool in conversation: mcp__api5io__toolname
  5. Result: "No such tool available" error

Expected Behavior:
HTTP MCP tools should be available in conversation interface just like STDIO MCP tools.

Actual Behavior:

  • ✅ CLI shows MCP server as "✓ Connected"
  • ✅ MCP protocol communication works (initialize, tools/list, resources/list)
  • ✅ /mcp UI shows server but no "View Tools" option
  • ❌ Tools not available with mcp__server__tool format in conversation
  • ❌ Tools not accessible for direct use in conversations

Technical Details:

Working MCP Protocol Responses:
// tools/list response (works correctly)
{
"jsonrpc": "2.0",
"id": 1,
"result": {
"tools": [
{
"name": "api5io_status",
"description": "Get the status of API5IO services",
"inputSchema": {
"type": "object",
"properties": {
"service": {
"type": "string",
"description": "The service name to check"
}
}
}
}
// ... other tools
]
}
}

Server Logs Show Successful Communication:
INFO: MCP request received: {"method": "initialize", "params": {"protocolVersion": "2025-11-25", "capabilities": {"roots": {}}, "clientInfo": {"name": "claude-code", "version": "2.0.76"}}}
INFO: MCP request received: {"method": "tools/list", "jsonrpc": "2.0", "id": 1}
INFO: MCP request received: {"method": "resources/list", "jsonrpc": "2.0", "id": 2}

Comparison with Working STDIO Servers:

  • STDIO servers (git-server, jira-server, etc.) work perfectly in conversation interface
  • HTTP servers connect but don't integrate with conversation tools

Impact:
HTTP MCP servers cannot be used for conversational AI assistance, limiting their practical utility compared to STDIO servers.

What Should Happen?

there should be View Tools option for /mcp, but not. Claude codo also donot know the tool to use.

Error Messages/Logs

Steps to Reproduce

a python based remote server

Claude Model

Sonnet (default)

Is this a regression?

I don't know

Last Working Version

_No response_

Claude Code Version

2.0.76

Platform

Anthropic API

Operating System

macOS

Terminal/Shell

Terminal.app (macOS)

Additional Information

_No response_

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