Claude CLI (claude-code) Fatal Memory Allocation Failure

Summary

Claude CLI consistently crashes with "JavaScript heap out of memory" error across multiple environments, regardless of available system memory or configured heap size.

Affected Version

• claude-code: v1.0.55 (latest as of report)
• Also affects: v1.0.54

Reproduction Rate

100% - Crashes every time on command execution

Environments Tested

Environment 1: Linux Server (Hetzner VPS)

OS: Ubuntu 22.04 LTS
Architecture: x86_64
Total RAM: 2GB
Available RAM: 1.6GB
Node: v18.19.1
npm: 9.2.0
Installation method: npm install -g @anthropic-ai/claude-code

Environment 2: Windows Desktop

OS: Windows 11
Architecture: x64
Total RAM: 32GB (33,525,028 KB)
Available RAM: 21GB (22,145,240 KB)
Node: v20.19.4
npm: (included with Node)
Installation method: npm install -g @anthropic-ai/claude-code

Error Details

Stack Trace (Linux):

FATAL ERROR: Reached heap limit Allocation failed - JavaScript heap out of memory
 1: 0x7df054a0633c node::Abort() [/lib/x86_64-linux-gnu/libnode.so.109]
 2: 0x7df0548fa5db  [/lib/x86_64-linux-gnu/libnode.so.109]
 3: 0x7df054dec544 v8::Utils::ReportOOMFailure(v8::internal::Isolate*, char const*, bool)
 4: 0x7df054dec938 v8::internal::V8::FatalProcessOutOfMemory(v8::internal::Isolate*, char const*, bool)
[... truncated for brevity ...]

Stack Trace (Windows):

FATAL ERROR: Reached heap limit Allocation failed - JavaScript heap out of memory
----- Native stack trace -----
 1: 00007FF75EF80CD7 node::SetCppgcReference+16599
 2: 00007FF75EEE4568 v8::base::CPU::num_virtual_address_bits+103336
[... truncated for brevity ...]

Command Used

claude --dangerously-skip-permissions --model claude-opus-4-20250514

Heap Limit Observations

Linux Default:

• Without NODE_OPTIONS: 984 MB
• With NODE_OPTIONS="--max-old-space-size=1536": Still crashes
• System has 1.6GB available but crashes at <1GB heap

Windows Default:

• Without NODE_OPTIONS: 4.05 GB
• With NODE_OPTIONS="--max-old-space-size=8192": 8.05 GB (still crashes)
• With NODE_OPTIONS="--max-old-space-size=16384": Not tested yet
• System has 21GB available but crashes at 4GB heap

Diagnostic Commands Run

Linux Diagnostics:

node -e "console.log(require('v8').getHeapStatistics().heap_size_limit / 1024 / 1024 + ' MB')"
# Output: 984 MB

echo $NODE_OPTIONS
# Output: (empty initially)

which claude
# Output: /home/claude/.npm-global/bin/claude

npm list -g | grep claude
# Output: └── @anthropic-ai/claude-code@1.0.55

Windows Diagnostics:

node -e "console.log((require('v8').getHeapStatistics().heap_size_limit / 1024 / 1024 / 1024).toFixed(2) + ' GB')"
# Output: 4.05 GB

$env:NODE_OPTIONS="--max-old-space-size=8192"
npx node -e "console.log(process.env.NODE_OPTIONS)"
# Output: --max-old-space-size=8192 (confirms NODE_OPTIONS is passed correctly)

Key Findings

1. Not a simple memory limit issue: Crashes occur well before system memory limits
2. NODE_OPTIONS is respected: Heap limits increase as expected, but crashes still occur
3. Cross-platform: Identical behavior on Linux (2GB) and Windows (32GB)
4. Happens immediately: Crashes during startup/initialization, not during operation
5. npx vs direct execution: Same result both ways

Attempted Solutions (All Failed)

1. ✗ Increasing NODE_OPTIONS heap size
2. ✗ Running with direct node command instead of wrapper
3. ✗ Using npx vs global installation
4. ✗ Adding swap space (Linux)
5. ✗ Different Node versions (18.x vs 20.x)

Expected Behavior

CLI should start and accept commands without crashing, especially on a system with 32GB RAM

Actual Behavior

Immediate crash with heap allocation failure

Additional Context

• No large files being processed
• No previous state/cache that could be corrupted
• Fresh installations on both systems
• Other Node applications work fine on both systems

Questions This Preemptively Answers

• Q: Is NODE_OPTIONS being passed? A: Yes, verified via diagnostics
• Q: Is it system memory? A: No, happens on 32GB system with 21GB free
• Q: Is it Node version specific? A: No, happens on v18.19.1 and v20.19.4
• Q: Is it OS specific? A: No, happens on Ubuntu 22.04 and Windows 11
• Q: Could it be npx? A: No, direct execution also fails
• Q: Is the installation corrupted? A: No, fresh installs on both systems

Suspected Root Cause

The CLI appears to be attempting to allocate massive amounts of memory during initialization, possibly:

• Loading large model files into memory
• Memory leak in initialization code
• Inefficient memory allocation pattern that fragments heap

Impact

Complete inability to use Claude CLI on any system, regardless of specifications