slack-mcp-server shows as "connected" but Claude Code can't see any tools?

[fbartho]

When I ask Claude Code it to verify access to slack using the mcp, it said: "the slack-mcp-server tools never loaded into my toolset - the server shows "Connected" but no mcp__slack__* tools appear."

I absolutely could have configured something wrong, but claude verified it could access the slack API directly using the tokens directly. So it's something else

Context:

• Claude Version: 2.0.61
• slack-mcp-server@1.1.26

Config:

 "slack": {
	"type": "stdio",
	"command": "npx",
	"args": ["-y", "slack-mcp-server"],
	"env": {
		"SLACK_MCP_XOXP_TOKEN": "xoxp-[snip]",
		"SLACK_MCP_TEAM_ID": "[snip]",
		"SLACK_MCP_ADD_MESSAGE_TOOL": "true"
	}
},

Are there any obvious pointers on what I did wrong?

[korotovsky]

There is definitely a configuration error, MCP Server from this repo does not have env with name SLACK_MCP_TEAM_ID. But it should not lead to the described behavior anyway, must be something else.

[fbartho]

I removed the nonsense env-var it had hallucinated, and still no dice.

No. Server shows "Connected" but still no mcp__slack__* tools in my toolset.

  This appears to be a compatibility issue between slack-mcp-server (Go binary) and Claude Code -
   the server connects but doesn't expose tools properly. The scripts workaround is working
  though

In no way do I blame you @korotovsky.

Claude Code was infuriatingly shit at configuring itself correctly with these MCPs (I was setting Slack, Linear, Notion, and Figma to try to use Claude as a project manager/personal assistant for myself).

It constantly hallucinated packages that don't exist. Including packages supposedly from anthropic. Even when I gave it the official documentation pages for each official integration, it still struggled.

It then read Anthropic's docs around defer_loading and then took 2 hours to decide that Claude Code doesn't support that yet, only Claude-web or it's in beta or something else.

Anyhow, if you have any pointers on how I can validate the MCP "should" be exposing those tools, I'd appreciate it. Thanks for confirming there was nonsense going on.

[korotovsky]

@fbartho do you still have the issue or resolved it?

[fbartho]

@korotovsky I never resolved the problems I reported above, no.

I wrote a quick workaround using curl and the Slack HTTP API for my use case.

Did you fix something that I should test? Happy to take a look if so.