MCP tools connect successfully but only if explicitly called by prompt, hammer icon / UI indicator never appears to allow view or management of tools

[oldgranola]

Bug Report: MCP tools connect successfully if explicitly called by prompt but hammer icon / UI indicator never appears

Environment: claude-desktop-debian installed on Linux Mint 22.3 Cinnamon

App version: 1.1.5749
Package: claude-desktop-debian (aaddrick)
OS: Linux Mint 22.3 (Cinnamon desktop, X11)
Arch: x64
Node: 24.14.0

---

Summary

MCP servers connect successfully at startup and tools are fully callable during
conversations if explicitly called, but the hammer icon / MCP tools indicator never appears in the
chat input bar. There is also no visible menu or panel showing which MCP servers
are connected. The only way to invoke tools is to explicitly name the MCP server
in a prompt. Without explicitly calling the MCP server use, the chat cannot find or use them and remarks that they do not exist.

---

Expected behaviour

After Claude Desktop starts with MCP servers configured in
claude_desktop_config.json, a hammer icon should appear in the chat input bar.
Clicking it should show the list of connected servers and available tools.

Actual behaviour

• No hammer icon appears in the chat input bar
• No MCP tools panel or indicator is visible anywhere in the UI
• The Settings page shows no indication of connected servers
• However: all three configured MCP servers connect successfully in the
  background (confirmed via mcp.log and by tools responding to calls within
  conversations when explicitly prompted)

---

Configuration

~/.config/Claude/claude_desktop_config.json:

{
  "mcpServers": {
    "podman": {
      "command": "/home/john/.venv/bin/podman-mcp-server",
      "args": [],
      "env": {
        "PODMAN_SOCK": "/run/user/1000/podman/podman.sock"
      }
    },
    "filesystem": {
      "command": "npx",
      "args": ["-y", "@modelcontextprotocol/server-filesystem", "/home/john"]
    },
    "github": {
      "command": "podman",
      "args": ["run", "-i", "--rm", "-e", "GITHUB_PERSONAL_ACCESS_TOKEN",
               "ghcr.io/github/github-mcp-server"],
      "env": {
        "GITHUB_PERSONAL_ACCESS_TOKEN": "***redacted***"
      }
    }
  }
}

---

Evidence that MCP servers ARE connecting (mcp.log extract)

2026-03-16T21:35:32.213Z [info] [filesystem] Server started and connected successfully
2026-03-16T21:35:32.268Z [info] [github] Server started and connected successfully
2026-03-16T21:35:35.181Z [info] [podman] Message from server: {"jsonrpc":"2.0","id":0,
  "result":{"capabilities":{"logging":{},"tools":{}},"protocolVersion":"2025-11-25",
  "serverInfo":{"name":"podman-mcp-server","version":"v0.0.15"}}}
2026-03-16T21:35:35.689Z [info] [filesystem] Message from server: {"jsonrpc":"2.0","id":0,
  "result":{"protocolVersion":"2025-11-25","capabilities":{"tools":{"listChanged":true}},
  "serverInfo":{"name":"secure-filesystem-server","version":"0.2.0"}}}
2026-03-16T21:35:36.200Z [info] [podman] tools/list response received: 13 tools
2026-03-16T21:35:36.466Z [info] [filesystem] tools/list response received: 14 tools
2026-03-16T21:35:36.935Z [info] [github] tools/list response received: 38 tools

All three servers complete initialize and tools/list handshakes without error.
Tool calls also succeed (e.g. list_directory, read_file etc. return correct
results within the same session).

main-window.log

No JavaScript errors. Only the repeated Electron CSP warning (expected in this
package):

[warn] Electron Security Warning (Insecure Content-Security-Policy) ...
This warning will not show up once the app is packaged.

No other renderer-process errors observed.

---

Relationship to issue #216

This is distinct from #216. In #216 the MCP servers are not connecting at all and
the UI correctly reports "No servers added." In this issue, the servers are
connecting and tools are functional — the UI simply never reflects that. The
backend is healthy; the hammer icon / tool indicator UI component appears not to
render on Linux (X11 / Cinnamon).

---

Steps to reproduce

1. Install claude-desktop-debian on Linux Mint 22.3 (Cinnamon, X11)
2. Add one or more MCP servers to ~/.config/Claude/claude_desktop_config.json
3. Launch Claude Desktop
4. Observe mcp.log — servers connect successfully
5. Observe chat input bar — no hammer icon present
6. Observe that explicitly prompting "use the filesystem MCP tool to list X"
   causes the tool to be called successfully

---

Impact

The missing UI indicator means:

• No visual confirmation that MCP tools are active
• No way to browse available tools without inspecting config files manually
• Users may believe tools are broken when they are actually functional
• Tools are only accessible by explicitly naming them in prompts, which is
  not intuitive and not documented behaviour

---

Additional notes

• Tested across multiple app restarts — behaviour is consistent
• The mcp.log shows tool calls completing successfully throughout the session,
  confirming the issue is purely in the frontend rendering layer

[oldgranola]

No tools or hammer icon. Also no such function in left pain (not shown)

[DiBop]

Confirmed on Linux Mint 22.1 (Cinnamon, X11), claude-desktop v1.1.5749

Same behavior — MCP servers connect and tools respond when explicitly called by name in a prompt, but the hammer icon never appears in the input bar.

mcp.log shows successful connection and tool list handshake. No errors in main-window.log beyond the standard Electron CSP warning. Issue is consistent across restarts.

The fact this reproduces on 22.1 suggests it's not specific to Mint 22.3 — likely an upstream rendering issue with X11/Cinnamon across Mint versions.

-- This was generated by Claude

[aaddrick]

Hey! I spent a good chunk of time digging into this one.

The short version: MCP tools work fine on Linux. The "hammer icon" doesn't exist anymore in the current UI. Anthropic redesigned the web frontend and moved MCP access to a different spot.

Your MCP servers should show up in two places now:

1. Settings > Developer > Local MCP servers for managing configurations
2. The + button in the chat input > Connectors for selecting servers to use in a conversation

I confirmed the backend plumbing is solid. listMcpServers() returns configured servers, isLocalDevMcpEnabled returns true, servers start and connect properly, and tools work when invoked. The desktop app is doing its job.

For reference, your ~/.config/Claude/claude_desktop_config.json should have a mcpServers key like this:

{
  "mcpServers": {
    "filesystem": {
      "command": "npx",
      "args": ["-y", "@modelcontextprotocol/server-filesystem", "/home/youruser"]
    }
  }
}

Restart Claude Desktop after adding that. The server should appear in Settings > Developer and under + > Connectors.

I traced through the Electron preload code and main process pretty thoroughly. Feature flags (chillingSlothFeat, louderPenguin), the process.platform exposure via contextBridge, the getSupportedFeatures() IPC call, the isLocalDevMcpEnabled endpoint. I patched platform checks and feature gates to see if anything would surface the old icon. None of it mattered because the icon was removed from the web UI entirely. The access point just moved.

Can you check whether your MCP servers show up under + > Connectors? If they do, I think we can close this out.

---

Written by Claude Opus 4.6 via Claude Code

[sagisar1]

@aaddrick Thank you for this response, I had the same problem and I can confirm that I see the mcp servers in the places you said

[oldgranola]

Thank you @aaddrick ! As you note, guess its moot now anyway with their UI change into the 'customize' icon. That still isn't very descriptive or obvious to a new user but easy enough. Just wish I didn't have to explicitly remind claude that I'm using the claude desktop and to load them every dang chat!