MCP server shows Connected but tools not discovered (@supabase/mcp-server-supabase)

Description

The @supabase/mcp-server-supabase MCP server shows as "Connected" in claude mcp list, but its tools are not discoverable via MCPSearch and cannot be invoked directly.

Environment

• Claude Code version: 2.1.12
• OS: macOS Darwin 25.2.0
• MCP Server: @supabase/mcp-server-supabase (latest via npx)

Configuration

{
  "supabase": {
    "type": "stdio",
    "command": "npx",
    "args": ["-y", "@supabase/mcp-server-supabase"],
    "env": {
      "SUPABASE_ACCESS_TOKEN": "sbp_xxxxx..."
    }
  }
}

Steps to Reproduce

1. Add supabase MCP server with valid access token:

``bash
claude mcp add supabase -s local -e SUPABASE_ACCESS_TOKEN="$TOKEN" -- npx -y @supabase/mcp-server-supabase
``

1. Restart Claude Code

1. Verify server is connected:

``bash
claude mcp list
# Shows: supabase: npx -y @supabase/mcp-server-supabase - ✓ Connected
``

1. Try to use any supabase tool - fails with "No such tool available"

Expected Behavior

Tools like mcp__supabase__list_projects, mcp__supabase__execute_sql should be available.

Actual Behavior

• claude mcp list shows server as "✓ Connected"
• claude mcp get supabase shows correct config including env vars
• MCPSearch returns "No matching MCP tools found"
• Direct tool invocation fails: "Error: No such tool available"

Verification that MCP Server Works

Testing the server directly confirms it exposes 30 tools correctly:

echo '{"jsonrpc":"2.0","id":1,"method":"tools/list"}' | \
  SUPABASE_ACCESS_TOKEN="$TOKEN" npx -y @supabase/mcp-server-supabase

Returns full tools list including list_projects, execute_sql, list_tables, etc.

Workaround

Direct PostgreSQL connection to Supabase works - only MCP tool discovery is broken.

Additional Context

• The access token is valid (verified via direct API call to https://api.supabase.com/v1/projects)
• Other MCP servers (memory, playwright, github, etc.) work fine
• Multiple restart cycles of Claude Code didn't resolve the issue
• Removing and re-adding the server didn't help

🤖 Generated with Claude Code