Memory leak: Missing cleanup for /tmp/claude-*-cwd working directory tracking files

[Sundeepg98]

Bug Description

Claude Code creates temporary files to track working directory changes across Bash command executions but never deletes them, causing accumulation of /tmp/claude-*-cwd files.

Environment

• Claude Code Version: 2.0.1
• OS: Linux (WSL2)
• Node Version: (System default)

The Problem

Every Bash tool invocation creates a temporary file at /tmp/claude-{random-4-hex}-cwd to track the working directory after command execution. These files are never cleaned up, leading to accumulation.

Evidence

• Observed: 174 files accumulated in one day of usage
• Pattern: Each file is 22 bytes containing the working directory path
• Debug log: Shows 2,018 Bash invocations over 4 days
• Only cleanup: systemd-tmpfiles-clean removes them daily at 07:15

Root Cause Analysis

Location in Code

File: /usr/local/lib/node_modules/@anthropic-ai/claude-code/cli.js

The issue is in the lq6 function (around line 1520 in the minified code):

// Current implementation (BUG - no cleanup):
P.result.then(async(k)=>{
  if(k&&!Y&&!k.backgroundTaskId)try{
    j$(bq6(K,{encoding:"utf8"}).trim(),M)  // Reads file but never deletes it
  }catch{
    B1("tengu_shell_set_cwd",{success:!1})
  }
})

The Mechanism

1. Claude Code generates a random temp file path: let K = \${V}/claude-${F}-cwd``
2. Appends pwd -P >| ${K} to every Bash command to capture final directory
3. Reads the file with bq6(K,{encoding:"utf8"}) to update internal cwd
4. Missing step: Never calls unlinkSync(K) to delete the file

The Fix

Add cleanup immediately after reading the file:

// Fixed implementation:
P.result.then(async(k)=>{
  if(k&&!Y&&!k.backgroundTaskId)try{
    let cwdContent=bq6(K,{encoding:"utf8"}).trim();
    try{C1().unlinkSync(K)}catch{};  // <- Add this line
    j$(cwdContent,M)
  }catch{
    B1("tengu_shell_set_cwd",{success:!1})
  }
})

Verification

I applied this fix locally and confirmed:

• Files are now created and immediately deleted after use
• Working directory tracking continues to function correctly
• No accumulation even after running 15+ commands in succession

Impact

• Resource leak: Accumulates filesystem entries (500+ files/day for heavy users)
• Privacy concern: Working directory paths persist in /tmp
• Disk usage: While minimal (22 bytes each), it's unnecessary accumulation

Reproduction Steps

1. Run any Bash command: ls
2. Check temp files: ls /tmp/claude-*-cwd
3. Observe new file created but not deleted
4. Repeat and watch accumulation

Why This Design Exists

The temp file approach is actually clever and necessary:

• Tracks cd commands across subprocess isolation
• Doesn't pollute stdout with pwd output
• Works reliably across all shell types
• The implementation is 95% correct, just missing the cleanup step

Recommendation

This is a simple one-line fix that should be included in the next Claude Code release. The temp file mechanism itself is sound and necessary for stateful directory navigation in a stateless subprocess model.

Additional Notes

• The fix has been tested and verified locally
• No side effects observed
• This affects all Claude Code users on Unix-like systems

[Sundeepg98]

Additional Analysis & Impact Assessment

Quantitative Impact Data

After monitoring for 24 hours, here's the accumulation rate:

• 174 orphaned files created in ~12 hours of usage
• 2,018 Bash invocations tracked in logs
• ~14.5 files/hour accumulation rate during active use
• 22 bytes each = minimal individual impact but compounds over time

Why This Matters

1. Multi-user systems: Shared servers could accumulate thousands of files
2. Long-running sessions: Power users running Claude Code 24/7
3. CI/CD environments: Automated systems without regular reboots
4. Docker containers: May not have systemd-tmpfiles-clean

Reproduction Script

#!/bin/bash
# Monitor temp file accumulation
echo "Starting temp file monitor..."
INITIAL_COUNT=$(ls /tmp/claude-*-cwd 2>/dev/null | wc -l)
echo "Initial count: $INITIAL_COUNT files"

# Trigger some Bash commands through Claude Code
for i in {1..10}; do
  # This would need to be triggered through Claude Code's UI/API
  echo "Trigger Bash command #$i through Claude Code"
  sleep 1
done

FINAL_COUNT=$(ls /tmp/claude-*-cwd 2>/dev/null | wc -l)
echo "Final count: $FINAL_COUNT files"
echo "Accumulated: $((FINAL_COUNT - INITIAL_COUNT)) new files"

Suggested Priority

Given the silent nature of this bug (no errors, just accumulation), I'd suggest Medium Priority with the following reasoning:

• ✅ Has a simple one-line fix
• ✅ Affects all users universally
• ⚠️ No immediate functionality impact
• ⚠️ Mitigated by system cleanup on most Linux distros
• ❌ Could cause issues on constrained systems

Testing the Fix

The fix has been verified locally by modifying /usr/local/lib/node_modules/@anthropic-ai/claude-code/cli.js:

// After line containing readFileSync(K)
try { require('fs').unlinkSync(K) } catch {}

Happy to provide any additional information or testing assistance needed!

[KCW89]

Have we resolved this issue?