Claude Code Bug: MCP Working Directory Reset

Hey guys, let's dive into a frustrating bug I've encountered while working with Claude Code and its MCP servers. If you're using this tool, you might run into the same issue. Basically, the working directory gets reset unexpectedly under certain conditions. Let's break it down, understand the problem, and look at potential solutions. This bug relates to how Claude Code handles working directories (cwd) for MCP servers defined in the .mcp.json file. It seems that the server's name plays a crucial role in whether the specified working directory is respected or overridden. Let's get into the nitty-gritty and how to fix this annoying problem. The main keyword of this article is MCP server working directory, which is the core of this bug report.

The Bug: Working Directory Reset

Alright, so here's the deal. When you set up your MCP servers in the .mcp.json file, you might use bash cd commands to change the working directory for each server. The goal is to have each server operate within a specific project directory. However, a weird thing happens: the working directory is forcibly reset to the current VSCode workspace path for some servers, but not for others. The frustrating part? The only visible difference between the servers that work and those that don't is their names.

Specifically, servers whose names do NOT start with the workspace directory's name have their cwd reset to the workspace path. On the other hand, servers whose names do start with the workspace directory name behave as expected. They correctly use the working directory specified in the configuration. This behavior is inconsistent and can cause a lot of headaches, especially when working with multiple projects or when project structures require different working directories for each server.

Imagine you have a VSCode workspace set up at /home/user/workspace/main-project. You've got an MCP server, let's say other-project, configured in .mcp.json to change the directory to /home/user/workspace/other-project before running claude mcp serve. You expect the server to operate within the other-project directory. But, due to this bug, the cwd is reset to the workspace root: /home/user/workspace/main-project. This leads to confusion and potentially incorrect behavior. This issue is a significant problem when setting up Claude Code with various project configurations. This article helps developers to quickly address and work around this bug.

Impact of the Bug

The impact of this bug can be substantial, leading to:

• Incorrect File Paths: When the working directory is reset, file paths that the server uses will be incorrect. This can cause the server to fail to find the necessary files or resources.
• Broken Functionality: The server's functionality might break entirely if it relies on being in a specific directory to execute commands or access certain files.
• Debugging Difficulties: It's tricky to track down the root cause of the issue since there's no visible error message. You'll waste time trying to figure out why the server isn't behaving as expected.
• Wasted Time: Developers waste time troubleshooting the issue and trying different configuration options to get the server to work. This frustration can slow down productivity.
• Inconsistent Behavior: If the naming convention isn't consistent, it can be hard to predict which server will work and which will fail. This adds to the overall confusion.

What Should Happen? The Correct Behavior

Ideally, all MCP servers should respect the working directory that's set by the bash cd command within their configuration. This means that regardless of the server name, the server should start and operate from the directory specified in the args array of the .mcp.json file. This consistency is essential for several reasons.

• Predictability: When the working directory is respected, the server's behavior becomes predictable. Developers can then easily understand and control where the server is executing commands and accessing files.
• Flexibility: The cd command in the configuration enables developers to organize servers to work from any desired directory, no matter how the project is structured.
• Reproducibility: If the working directory is honored, the setup becomes more reproducible. Configuration files can be reliably used across different machines and environments.
• Ease of Use: Developers will be able to easily configure servers without having to resort to workarounds. This makes the tool easier to use and more intuitive.
• Maintainability: Code can be easily maintained and updated when the expected behavior is consistent.

The developers must ensure the working directory is correctly set up. It increases user satisfaction and reduces development time.

Steps to Reproduce the Bug

Let's get into how you can reproduce this bug. Following the below steps should help you replicate the issue on your system, which will help in resolving the problem.

1. Set Up the Workspace: Open VSCode with a workspace at /home/user/workspace/main-project. Make sure your workspace is set up correctly, with the necessary files and folders for your project.
2. Create .mcp.json: Create a .mcp.json file in the root of the workspace. This file will hold your MCP server configurations. It's the core of the problem, so ensure that you set it up correctly with at least two servers as follows:

{
  "mcpServers": {
    "other-project": {
      "command": "/bin/bash",
      "args": ["-c", "cd /home/user/workspace/other-project && claude mcp serve"]
    },
    "main-project-sub": {
      "command": "/bin/bash",
      "args": ["-c", "cd /home/user/workspace/sub-project && claude mcp serve"]
    }
  }
}

*   In the example above, we're setting up two servers: `other-project` and `main-project-sub`. The `other-project` server is configured to change the directory to `/home/user/workspace/other-project`, and the `main-project-sub` server changes the directory to `/home/user/workspace/sub-project`.

3. Restart VSCode: After you create the .mcp.json file, restart VSCode to ensure that the changes are applied and that Claude Code reloads the configurations.

4. Use the Bash Tool: Use each MCP server's Bash tool. You can open a terminal instance within VSCode, and run pwd to get the current working directory.

5. Observe the Results: After running pwd for each server, you'll see the bug in action:

   • other-project will report /home/user/workspace/main-project (this is incorrect – it's been reset to the workspace).
   • main-project-sub will report /home/user/workspace/sub-project (this is correct, as expected).

   The differing behavior is due to the server names and whether they start with the workspace directory name or not.

By following these steps, you can directly reproduce the bug and verify that the server name affects the working directory in Claude Code.

The Observed Pattern

Here's a quick summary of the pattern we've observed. This table should help you understand the core issue and how the server name affects the working directory.

As you can see, the crucial factor is whether the server name begins with the workspace name. If it does, the cwd behaves as expected. If it doesn't, the cwd gets reset to the workspace path.

The Workaround: Rename the Servers

Okay, so what do you do if you're running into this bug? The solution is straightforward: rename your MCP servers to start with the workspace directory name. It's not the most elegant solution, but it's effective. Let's look at how it works.

Example:

• Problematic Name: other-project (does not start with workspace name).
• Solution: Change the server name to main-project-fe (assuming the workspace name is main-project).

By renaming the server in this way, you ensure that the server's name begins with the workspace directory name. This change forces the cwd to behave correctly. You must update your .mcp.json file with the new name. And you're good to go.

Important Considerations

• Configuration Updates: Make sure you update any scripts or configurations that reference the server's original name. All the references to the server must reflect the new name for the workaround to function correctly.
• Project Structure: The workaround can become cumbersome if you're dealing with projects whose names are long. Try to keep the workspace name short for practicality.

While this workaround resolves the immediate issue, it's best if the underlying bug is fixed. This ensures the correct behavior regardless of the server name.

Attempted Fixes (All Failed)

I've tried different approaches to address this problem. The following fixes didn't work:

1. Using env.PWD in Server Config: I tried to use env.PWD in the server configuration to set the cwd, but it didn't solve the issue. The environment variable didn't behave as I expected it to, and the working directory was still reset.
2. Using cwd Field in Server Config: I also attempted to use the cwd field in the server configuration to explicitly set the working directory. But it didn't work; the cwd field was overridden by the bug.
3. Using --cwd Flag: I explored the possibility of using the --cwd flag with the claude mcp serve command, but unfortunately, it's not supported by the tool.
4. Changing Server Order: I changed the order of the servers in the .mcp.json file. But it didn't make any difference; the bug persisted regardless of the order.
5. Disabling Hooks: I tried to disable hooks in the target project's .claude/settings.json file. Disabling hooks didn't solve the problem, and the working directory was still reset.

Suggested Investigation

Here are some of the areas that could be responsible for the issue. Debugging this issue can be challenging. However, there are a few areas in the code that we should consider. These will help developers pinpoint the root cause of the bug.

1. MCP Server Initialization Logic: The MCP server initialization logic may be the culprit. The code might be checking if the server name matches or begins with the workspace name. If the check fails, the code may be forcibly setting the cwd to the workspace path. Inspecting this part of the code could reveal why the working directory is being reset.
2. Path Resolution: Path resolution issues might be at play. Incorrect path resolution could be leading to the cwd being set to the workspace directory. Examine the path resolution logic within Claude Code to check if it's correctly identifying the correct working directory.
3. Security Feature: It is possible that this behavior is by design, potentially as an undocumented security feature. If this is true, the developers need to document the behavior for other developers to better understand the tool.

By carefully checking these aspects of the Claude Code implementation, the developers will be able to resolve the problem. Hopefully, it will ensure that the working directory is set up correctly in all cases.