Filesystem MCP server crashes silently on paths containing ~ (tilde) character

[skl-chip]

Filesystem MCP server crashes silently on directory paths containing leading ~ (tilde) character

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Environment:

• Claude Desktop: Latest (as of February 26, 2026)
• macOS: Sequoia (Apple Silicon)
• Node.js: v25.4.0 (Homebrew)
• MCP Filesystem Extension: Installed via Claude Desktop extensions marketplace

Description:

The Filesystem MCP server crashes silently when any of the configured allowed directories contains a leading tilde (~) as a literal character in the folder name (e.g., /Volumes/Drive/Projects/~MyFolder). This is a valid and common naming convention used to force important folders to sort to the top of a directory listing.

The server starts successfully, receives the initialize handshake from the client, then immediately exits with no error message or stack trace. The failure is silent — nothing in the logs indicates what went wrong.

Log snippet showing failure pattern:

2026-02-26T15:12:22.731Z [Filesystem] [info] Server started and connected successfully
2026-02-26T15:12:22.867Z [Filesystem] [info] Message from client: {"method":"initialize","params":{"protocolVersion":"2025-11-25"...}
2026-02-26T15:12:22.877Z [Filesystem] [info] Server transport closed unexpectedly, this is likely due to the process exiting early.
2026-02-26T15:12:22.877Z [Filesystem] [error] Server disconnected.

Steps to reproduce:

1. Install the Filesystem MCP extension via Claude Desktop
2. Add an allowed directory whose name begins with ~ (e.g., /Volumes/Drive/Projects/~MyFolder)
3. Relaunch Claude Desktop
4. Observe server fails with "Server disconnected" and no descriptive error

Verification:

Running the server manually works without issue:

node "/Users/<user>/Library/Application Support/Claude/Claude Extensions/ant.dir.ant.anthropic.filesystem/server/index.js" "/Volumes/Drive/Projects/~MyFolder"

Output: Secure MCP Filesystem Server running on stdio

Removing the ~ prefix from the directory name resolves the issue immediately, confirming the tilde character is the root cause.

Expected behavior:

The server should either handle ~ as a literal character in directory paths, or throw a descriptive error identifying the problematic path rather than crashing silently.

Impact:

Using ~ as a prefix to sort important folders to the top of a directory listing is a common convention. Any user employing this pattern will hit this bug with no indication of what went wrong, requiring significant debugging effort to isolate.