# How to Use Memgraph for iOS Memory Leak Detection with the Build iOS Apps Plugin

> Detect iOS memory leaks effortlessly with Memgraph and the Build iOS Apps plugin. Capture heap snapshots and get instant markdown reports to pinpoint and fix memory issues.

- Repository: [OpenAI/plugins](https://github.com/openai/plugins)
- Tags: how-to-guide
- Published: 2026-07-04

---

**The Build iOS Apps plugin provides an automated iOS Memgraph Leaks skill that captures heap snapshots from iOS simulators and generates markdown reports to identify and root-cause memory leaks.**

The `openai/plugins` repository includes a specialized **Build iOS Apps** plugin that streamlines memory debugging for iOS applications. By leveraging the **iOS Memgraph Leaks** skill, developers can automate the capture and analysis of heap snapshots to detect retain cycles and unreachable objects without manual profiling in Xcode. This workflow integrates directly into CI pipelines, treating memory analysis as a reproducible quality gate rather than ad-hoc debugging.

## Understanding iOS Memgraph Snapshots

A **memgraph** is a binary-format snapshot of an iOS app's heap taken from a running simulator process. Unlike live debugging sessions, memgraph files provide deterministic snapshots that can be archived, compared across builds, and analyzed offline using macOS command-line tools. The Build iOS Apps plugin treats these snapshots as test artifacts, enabling regression verification and historical leak tracking.

## Automated Leak Detection Workflow

The **iOS Memgraph Leaks** skill automates a three-stage workflow designed for iterative debugging: capture, summarize, and investigate.

### Capture Memgraph from Simulator

The [`capture_sim_memgraph.sh`](https://github.com/openai/plugins/blob/main/capture_sim_memgraph.sh) script wraps Xcode's `xcrun memgraph` tool to extract heap data from a specific simulator instance. Located at [`plugins/build-ios-apps/skills/ios-memgraph-leaks/scripts/capture_sim_memgraph.sh`](https://github.com/openai/plugins/blob/main/plugins/build-ios-apps/skills/ios-memgraph-leaks/scripts/capture_sim_memgraph.sh), this script requires the target simulator UDID and app bundle identifier to produce a timestamped `.memgraph` file.

```bash
SKILL_DIR="/path/to/plugins/build-ios-apps/skills/ios-memgraph-leaks"
SIM="F2E3A4B5-1234-5678-90AB-CDEF12345678"
BUNDLE_ID="com.example.myapp"
MEMGRAPH_DIR="$(mktemp -d "${TMPDIR:-/tmp}/codex-ios-memgraph.XXXXXX")"

"$SKILL_DIR/scripts/capture_sim_memgraph.sh" \
  --udid "$SIM" \
  --bundle-id "$BUNDLE_ID" \
  --out-dir "$MEMGRAPH_DIR"

```

### Summarize Leaks with Python Analysis

After capture, the [`summarize_memgraph_leaks.py`](https://github.com/openai/plugins/blob/main/summarize_memgraph_leaks.py) script parses the memgraph using the macOS `leaks` command. This Python helper, found at [`plugins/build-ios-apps/skills/ios-memgraph-leaks/scripts/summarize_memgraph_leaks.py`](https://github.com/openai/plugins/blob/main/plugins/build-ios-apps/skills/ios-memgraph-leaks/scripts/summarize_memgraph_leaks.py), generates a structured markdown report containing total leak counts, top offending types, individual leak entries, and grouped-by-type trees for unreachable retain cycles.

```bash
"$SKILL_DIR/scripts/summarize_memgraph_leaks.py" \
  "$MEMGRAPH_DIR/<timestamp>.memgraph" \
  --trace-limit 5 \
  --out "./leak-summary.md"

```

The `--trace-limit` parameter controls how many `leaks --traceTree` excerpts appear in the report, providing immediate context for the most critical leaks without overwhelming noise.

### Root-Cause Investigation

For leaked objects identified in the summary, use `leaks --traceTree=<address>` to reveal ownership paths and retain cycles. If `traceTree` returns no roots, the `leaks --groupByType` flag helps categorize unreachable objects by their class types. The skill's documentation in [`SKILL.md`](https://github.com/openai/plugins/blob/main/SKILL.md) recommends iterating through these steps: apply the smallest possible fix, recapture the memgraph, and compare before/after results to verify the elimination of specific leak signatures rather than merely reducing total counts.

```bash
leaks --traceTree=0x12345678 "$MEMGRAPH_DIR/<timestamp>.memgraph"

```

## Integrating into Development Workflows

Because memgraph snapshots are deterministic binary artifacts, teams can store them alongside test results in CI pipelines. The workflow documented in [`plugins/build-ios-apps/skills/ios-memgraph-leaks/SKILL.md`](https://github.com/openai/plugins/blob/main/plugins/build-ios-apps/skills/ios-memgraph-leaks/SKILL.md) emphasizes a repeatable five-step process:

1. Build and drive the target UI flow that should release objects
2. Capture the memgraph from the simulator
3. Summarize the memgraph with the Python script
4. Inspect app-owned leaks with `leaks --traceTree`
5. Verify fixes through comparative analysis of recaptured snapshots

This approach transforms **memgraph for iOS memory leak detection** from manual investigation into a reproducible engineering practice.

## Summary

- **Memgraph snapshots** provide deterministic binary heap captures from iOS simulators, enabling offline analysis and CI integration.
- The **capture script** ([`capture_sim_memgraph.sh`](https://github.com/openai/plugins/blob/main/capture_sim_memgraph.sh)) automates `xcrun memgraph` execution using simulator UDID and bundle identifiers.
- The **summarization script** ([`summarize_memgraph_leaks.py`](https://github.com/openai/plugins/blob/main/summarize_memgraph_leaks.py)) parses `leaks` command output into actionable markdown reports with configurable trace limits.
- **Root-cause analysis** uses `leaks --traceTree` for ownership paths and `leaks --groupByType` for categorizing unreachable retain cycles.
- The complete workflow is documented in [`plugins/build-ios-apps/skills/ios-memgraph-leaks/SKILL.md`](https://github.com/openai/plugins/blob/main/plugins/build-ios-apps/skills/ios-memgraph-leaks/SKILL.md) within the `openai/plugins` repository.

## Frequently Asked Questions

### What is the difference between a memgraph file and Xcode's Memory Graph Debugger?

A memgraph file is a binary snapshot saved to disk, whereas Xcode's Memory Graph Debugger provides a live, interactive visualization. The memgraph format enables automated analysis in CI environments and allows engineers to compare heap states across different builds or code changes using command-line tools like `leaks`.

### Can I use the iOS Memgraph Leaks skill on physical devices?

No. According to the source implementation in `openai/plugins`, the [`capture_sim_memgraph.sh`](https://github.com/openai/plugins/blob/main/capture_sim_memgraph.sh) script specifically targets iOS simulators using `xcrun simctl` and simulator UDIDs. Physical device memory debugging requires different entitlements and transfer mechanisms not supported by this particular skill.

### How do I interpret when leaks --traceTree returns no root information?

When `traceTree` finds no ownership roots for a leaked object, use the `leaks --groupByType` flag to categorize leaks by their Objective-C or Swift class names. This often reveals systemic retain cycles within specific modules or third-party frameworks, as documented in the skill's [`SKILL.md`](https://github.com/openai/plugins/blob/main/SKILL.md) troubleshooting section.

### Is the Python summarization script compatible with custom memgraph files captured manually?

Yes. While designed to work with the capture script's output, [`summarize_memgraph_leaks.py`](https://github.com/openai/plugins/blob/main/summarize_memgraph_leaks.py) accepts any valid `.memgraph` file path as its positional argument. You can generate memgraphs manually via Xcode's "Debug Memory Graph" export feature or `xcrun memgraph` and still process them through the summarization pipeline for consistent reporting.