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Filesystem MCP server crashes silently on paths containing ~ (tilde) character #3412
Description
Activity
- added a commit that references this issue
on Mar 17, 2026 I could not reproduce this on current
main(f46d957) — it looks like the marketplace build predates the guards that were added since.What I ran (macOS ARM, Node 26): a full stdio MCP session against the built server with an allowed directory whose name starts with a literal tilde, exactly the reported shape:
mkdir -p '/tmp/mcp-test/~TildeProject' && echo 'hello tilde' > '/tmp/mcp-test/~TildeProject/note.txt' node dist/index.js /tmp/mcp-testSession transcript (JSON-RPC over stdio):
initialize→ ok (serverInfo: secure-filesystem-server)- startup log:
Client does not support MCP Roots, using allowed directories set from server args: [ '/tmp/mcp-test', '/private/tmp/mcp-test' ] tools/list→ ok, 14 toolstools/call list_directory {"path": "/tmp/mcp-test/~TildeProject"}→[FILE] note.txttools/call read_file {"path": "/tmp/mcp-test/~TildeProject/note.txt"}→hello tilde- no transport close, no exit
The current code is defensive at every step of the reported path:
expandHome(src/filesystem/path-utils.ts:119-124) only expands a leading~/or bare~, so/Volumes/…/~MyFolderpasses through untouched; startup validation skips inaccessible dirs with a warning instead of throwing (src/filesystem/index.ts:46-80); and the roots-protocol path wraps every conversion in try/catch (src/filesystem/roots-utils.ts:13-25,52-77).Given the reporter's log is from the Claude Desktop marketplace build (Feb 2026), the silent crash they hit was most likely in a build before those guards landed. #3414 (open since June, last activity 2026-06-13) also adds tilde-path test coverage for this area — maybe worth reviving or superseding so this report can be closed against a released build.
AI-assisted analysis note: the session above was executed locally by me against a fresh build of current
main; the transcript is verbatim.
Filesystem MCP server crashes silently on directory paths containing leading ~ (tilde) character
Environment:
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:
Steps to reproduce:
Verification:
Running the server manually works without issue:
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.