Tool Name Length Exceeds 64 Character Limit in API Request

[omarrns]

Bug Description
i connected my MCPs and now i can't use claude code ever. error message: "API Error: 400 {"type":"error","error":{"type":"invalid_request_error","message":"tools.63.custom.name: String should
have at most 64 characters"}}"

Environment Info

• Platform: darwin
• Terminal: windsurf
• Version: 1.0.31
• Feedback ID: db75f5c1-891d-4b3e-a1b2-5aed6cbdd992

Errors

[{"error":"Error: Command failed: security find-generic-password -a $USER -w -s \"Claude Code\"\nsecurity: SecKeychainSearchCopyNext: The specified item could not be found in the keychain.\n\n    at genericNodeError (node:internal/errors:983:15)\n    at wrappedFn (node:internal/errors:537:14)\n    at checkExecSyncError (node:child_process:882:11)\n    at execSync (node:child_process:954:15)\n    at NZ (file:///Users/omarnasser/.nvm/versions/node/v22.16.0/lib/node_modules/@anthropic-ai/claude-code/cli.js:700:3921)\n    at file:///Users/omarnasser/.nvm/versions/node/v22.16.0/lib/node_modules/@anthropic-ai/claude-code/cli.js:622:9014\n    at Q (file:///Users/omarnasser/.nvm/versions/node/v22.16.0/lib/node_modules/@anthropic-ai/claude-code/cli.js:526:17199)\n    at GX (file:///Users/omarnasser/.nvm/versions/node/v22.16.0/lib/node_modules/@anthropic-ai/claude-code/cli.js:622:8160)\n    at fS (file:///Users/omarnasser/.nvm/versions/node/v22.16.0/lib/node_modules/@anthropic-ai/claude-code/cli.js:622:7241)\n    at R9 (file:///Users/omarnasser/.nvm/versions/node/v22.16.0/lib/node_modules/@anthropic-ai/claude-code/cli.js:622:11408)","timestamp":"2025-06-23T17:24:45.375Z"},{"error":"Error: 400 {\"type\":\"error\",\"error\":{\"type\":\"invalid_request_error\",\"message\":\"tools.63.custom.name: String should have at most 64 characters\"}}\n    at d6.generate (file:///Users/omarnasser/.nvm/versions/node/v22.16.0/lib/node_modules/@anthropic-ai/claude-code/cli.js:1302:12578)\n    at yw.makeStatusError (file:///Users/omarnasser/.nvm/versions/node/v22.16.0/lib/node_modules/@anthropic-ai/claude-code/cli.js:1317:2082)\n    at yw.makeRequest (file:///Users/omarnasser/.nvm/versions/node/v22.16.0/lib/node_modules/@anthropic-ai/claude-code/cli.js:1317:5257)\n    at process.processTicksAndRejections (node:internal/process/task_queues:105:5)\n    at async N11.showErrors (file:///Users/omarnasser/.nvm/versions/node/v22.16.0/lib/node_modules/@anthropic-ai/claude-code/cli.js:1959:18554)\n    at async N11 (file:///Users/omarnasser/.nvm/versions/node/v22.16.0/lib/node_modules/@anthropic-ai/claude-code/cli.js:1492:703)\n    at async pU2 (file:///Users/omarnasser/.nvm/versions/node/v22.16.0/lib/node_modules/@anthropic-ai/claude-code/cli.js:1959:18400)\n    at async file:///Users/omarnasser/.nvm/versions/node/v22.16.0/lib/node_modules/@anthropic-ai/claude-code/cli.js:1959:13529\n    at async Oe1 (file:///Users/omarnasser/.nvm/versions/node/v22.16.0/lib/node_modules/@anthropic-ai/claude-code/cli.js:1959:4695)\n    at async Wu (file:///Users/omarnasser/.nvm/versions/node/v22.16.0/lib/node_modules/@anthropic-ai/claude-code/cli.js:1959:13499)","timestamp":"2025-06-23T17:24:47.475Z"}]

[ww2283]

same here. I added Docker Tool kit, and then see this error:

 API Error: 400 {"type":"error","error":{"type":"invalid_request_error","message":"tools.19.custom.name: String should have at most 64 characters"}}

Version: 1.102.0-insider
Commit: e2a90e99b9183d379ee0c501763d81d45804423c
Date: 2025-06-13T17:41:37.636Z
Electron: 35.5.1
ElectronBuildId: 11727614
Chromium: 134.0.6998.205
Node.js: 22.15.1
V8: 13.4.114.21-electron.0
OS: Darwin arm64 24.5.0

[anotherjung]

same here.

try adding mcp server manually to claude-code cli
docker desktop docker mcp toolkit stays
Connect other MCP clients to the same server by specifying the following command:
docker run -i --rm alpine/socat STDIO TCP:host.docker.internal:8811

remove config
claude mcp remove MCP_DOCKER

add config for running docker desktop with docker mcp toolkit
claude mcp add-json github '{ "command": "docker", "args": [ "run", "-i", "--rm", "alpine/socat", "STDIO", "TCP:host.docker.internal:8811" ] }'
claude mcp add-json Obsidian '{ "command": "docker", "args": [ "run", "-i", "--rm", "alpine/socat", "STDIO", "TCP:host.docker.internal:8811" ] }'

list added mcp
claude mcp list

agent prompts:
use github mcp tool
use Obsidian MCP tool
agent response:

I can help you use the Obsidian MCP tool. Let me first check what Obsidian tools are available to
  you.

[ashwin-ant]

dupe of #2412

[CXwudi]

I found a workaround for GitHub MCP server, change the MCP server name to something shorter so that the tool name stays within 64 characters, for example, use gh instead of github:

"gh": {
      "command": "docker",
      "args": [
        "run",
        "-i",
        "--rm",
        "-e",
        "GITHUB_PERSONAL_ACCESS_TOKEN",
        "ghcr.io/github/github-mcp-server"
      ],
      "env": {
        "GITHUB_PERSONAL_ACCESS_TOKEN": ""
      },
      "type": "stdio"
    }

Then the longest tool would stay within 64 characters:

add_pull_request_review_comment_to_pending_review (gh)                                                               │
│                                                                                                                      │
│ Full name: mcp__gh__add_pull_request_review_comment_to_pending_review

can you test if the github mcp is working?

● I'll test the GitHub MCP by checking what GitHub functionality is available and then trying a simple operation.
  ⎿  {
       "login": "CXwudi",

[github-actions]

This issue has been automatically locked since it was closed and has not had any activity for 7 days. If you're experiencing a similar issue, please file a new issue and reference this one if it's relevant.