Description

The ARM64/CoreML segfault mitigation in mempalace/__init__.py line 19 sets an environment variable that ONNX Runtime does not read, making the fix completely non-functional.

os.environ.setdefault("ORT_DISABLE_COREML", "1")

Root Cause

ORT_DISABLE_COREML is not a recognized ONNX Runtime environment variable. ONNX Runtime does not provide a global env var to disable individual execution providers.

This means:

• Setting this variable has zero effect on ONNX Runtime behavior
• The CoreMLExecutionProvider is still loaded on macOS ARM64
• The segfault documented in issue ChromaDB null pointer crash after ~8,400 drawers on macOS ARM64 #74 is not actually mitigated by this code

Verification

1. The ONNX Runtime CoreML documentation lists no such environment variable
2. Searching the ONNX Runtime source code for "ORT_DISABLE_COREML" returns zero results
3. Provider selection is controlled at the session level via InferenceSession(model, providers=[...]), not via environment variables

How to actually disable CoreML

The correct approach for ChromaDB's default embedding function:

from chromadb.utils.embedding_functions import ONNXMiniLM_L6_V2
ef = ONNXMiniLM_L6_V2(preferred_providers=["CPUExecutionProvider"])

Or when creating the ONNX session directly:

import onnxruntime as ort
session = ort.InferenceSession(model_path, providers=["CPUExecutionProvider"])

Impact

• macOS ARM64 users (M1/M2/M3) experience segfaults on vector queries
• The existing "fix" in __init__.py provides false confidence
• Issue ChromaDB null pointer crash after ~8,400 drawers on macOS ARM64 #74 was closed but the mitigation it references is non-functional
• ChromaDB's default embedding function still uses CoreML when available

Suggested Fix

Replace the no-op env var with an actual provider override:

# In mcp_server.py / miner.py wherever ChromaDB clients are created:
import platform
if platform.machine() in ("arm64", "aarch64") and platform.system() == "Darwin":
    ef = ONNXMiniLM_L6_V2(preferred_providers=["CPUExecutionProvider"])
    collection = client.get_or_create_collection("mempalace_drawers", embedding_function=ef)

Remove the no-op from __init__.py:

-os.environ.setdefault("ORT_DISABLE_COREML", "1")

Environment

• mempalace v3.0.13 (current main)
• __init__.py line 19
• Related: issue ChromaDB null pointer crash after ~8,400 drawers on macOS ARM64 #74 (closed — segfault symptom tracked but mitigation is broken)