[BUG]

Environment

• Platform (select one):
• [x] Anthropic API
• [ ] AWS Bedrock
• [ ] Google Vertex AI
• [ ] Other:
• Claude CLI version: 0.2.79 - 0.2.86
• Operating System: Debian 12
• Terminal: GNOME Terminal

Bug Description

ClaudeCode is unable to 'find' a MCP server tool which works correctly with v0.2.78

Steps to Reproduce

1. Start ClaudeCode with the MCP server definition, within a conda environment
2. Request usage of the tool
3. Observe 'Tool not found

Expected Behavior

Expect ClaudeCode to continue using the tool that worked in prior versions

Actual Behavior

\u25cf Now that I've identified the mypy issues, I'll use the Aider tool to help fix them. Let's start by addressing some of the most critical issues
in the files with the most errors.
ReferenceError: Tool not found for mcp__aider__aider_ai_code
at file:///home/xxx/.conda/envs/ClaudeCode/lib/node_modules/@anthropic-ai/claude-code/cli.js:1726:855
at Object.useMemo (file:///home/xxx/.conda/envs/ClaudeCode/lib/node_modules/@anthropic-ai/claude-code/cli.js:91:25822)
at M59.useMemo (file:///home/xxx/.conda/envs/ClaudeCode/lib/node_modules/@anthropic-ai/claude-code/cli.js:52:18366)
at Rg (file:///home/xxx/.conda/envs/ClaudeCode/lib/node_modules/@anthropic-ai/claude-code/cli.js:1726:706)
at fV6 (file:///home/xxx/.conda/envs/ClaudeCode/lib/node_modules/@anthropic-ai/claude-code/cli.js:1726:1768)
at sB (file:///home/xxx/.conda/envs/ClaudeCode/lib/node_modules/@anthropic-ai/claude-code/cli.js:91:19349)
at N_ (file:///home/xxx/.conda/envs/ClaudeCode/lib/node_modules/@anthropic-ai/claude-code/cli.js:93:42517)
at Q6 (file:///home/xxx/.conda/envs/ClaudeCode/lib/node_modules/@anthropic-ai/claude-code/cli.js:93:38085)
at ZO (file:///home/xxx/.conda/envs/ClaudeCode/lib/node_modules/@anthropic-ai/claude-code/cli.js:93:38013)
at FV (file:///home/xxx/.conda/envs/ClaudeCode/lib/node_modules/@anthropic-ai/claude-code/cli.js:93:37867)

ERROR Tool not found for mcp__aider__aider_ai_code

file:///home/xxx/.conda/envs/ClaudeCode/lib/node_modules/@anthropic-ai/claude-code/cli.js:1726:855

• (file:///home/xxx/.conda/envs/ClaudeCode/lib/node_modules/@anthropic-ai/claude-code/cli.js:1726:855)
• Object.useMemo (file:///home/xxx/.conda/envs/ClaudeCode/lib/node_modules/@anthropic-ai/claude-code/cli.js:91:25822)
• M59.useMemo (file:///home/xxx/.conda/envs/ClaudeCode/lib/node_modules/@anthropic-ai/claude-code/cli.js:52:18366)
• Rg (file:///home/xxx/.conda/envs/ClaudeCode/lib/node_modules/@anthropic-ai/claude-code/cli.js:1726:706)
• fV6 (file:///home/xxx/.conda/envs/ClaudeCode/lib/node_modules/@anthropic-ai/claude-code/cli.js:1726:1768)
• sB (file:///home/xxx/.conda/envs/ClaudeCode/lib/node_modules/@anthropic-ai/claude-code/cli.js:91:19349)
• N_ (file:///home/xxx/.conda/envs/ClaudeCode/lib/node_modules/@anthropic-ai/claude-code/cli.js:93:42517)
• Q6 (file:///home/xxx/.conda/envs/ClaudeCode/lib/node_modules/@anthropic-ai/claude-code/cli.js:93:38085)
• ZO (file:///home/xxx/.conda/envs/ClaudeCode/lib/node_modules/@anthropic-ai/claude-code/cli.js:93:38013)
• FV (file:///home/xxx/.conda/envs/ClaudeCode/lib/node_modules/@anthropic-ai/claude-code/cli.js:93:37867)

Additional Context

Server definition
"aider": {
"command": "uv",
"args": [
"--directory",
"/xxx/src/aider-mcp-server",
"run",
"mcp-aider-server",
"--editor-model",
"gemini/gemini-2.5-flash-preview-04-17",
"--current-working-dir",
"/xxx/aider-sse-worktree/with-sse-mcp"
],
"env": {}
}
https://github.com/disler/aider-mcp-server