
Ios Memgraph Leaks
- 56 installs
- 4.9k repo stars
- Updated July 14, 2026
- openai/plugins
ios-memgraph-leaks is an agent skill for capturing iOS simulator memgraphs, summarizing leaks, and proving retain-cycle fixes with scripts.
About
The ios-memgraph-leaks skill helps prove iOS memory leaks from live simulator processes or existing memgraph files using bundled capture and summarize scripts. The workflow builds and drives the reproduction flow, captures a memgraph with capture_sim_memgraph.sh using simulator UDID and bundle identifier, summarizes leaks via summarize_memgraph_leaks.py, and inspects app-owned types with leaks traceTree or groupByType evidence. Fixes require the smallest root-cause patch retaining-edge removal rather than broad cleanup, then recapture on the same simulator with before-and-after leak counts and disappeared types. Agents must not claim fixes from smaller memgraphs alone without explaining ownership paths. SKILL_DIR resolves to the loaded plugin folder, not the target app repo. Pair with ios-debugger-agent when builds, UI driving, logs, or screenshots are also needed. Triggers include debugging leaked objects, retain cycles, or memory growth on iOS simulators.
- Captures simulator memgraphs with capture_sim_memgraph.sh.
- Summarizes leaks via summarize_memgraph_leaks.py output.
- Requires ownership trace or grouped leak tree evidence.
- Mandates before-and-after recapture to prove fixes.
- Pairs with ios-debugger-agent for full simulator workflows.
Ios Memgraph Leaks by the numbers
- 56 all-time installs (skills.sh)
- +12 installs in the week ending Jul 26, 2026 (Skillselion tracking)
- Ranked #585 of 1,039 Mobile Development skills by installs in the Skillselion catalog
- Data as of Aug 4, 2026 (Skillselion catalog sync)
ios-memgraph-leaks capabilities & compatibility
- Capabilities
- simulator memgraph capture scripting · leak summarization with trace limits · ownership path and groupbytype analysis · before after leak regression proof · root cause retaining edge fix guidance
- Use cases
- debugging · testing
What ios-memgraph-leaks says it does
Capture and inspect iOS leaks and memgraphs.
Do not claim a leak fix from a smaller memgraph alone.
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| Installs | 56 |
|---|---|
| repo stars | ★ 4.9k |
| Last updated | July 14, 2026 |
| Repository | openai/plugins ↗ |
How do I prove an iOS leak fix with memgraph evidence from the simulator?
Capture iOS simulator memgraphs, summarize leaked objects, trace ownership paths, and prove before-and-after leak fixes with scripts.
Who is it for?
iOS developers debugging simulator leaks, retain cycles, or memory growth with memgraph tooling.
Skip if: Skip for Android memory profiling, production device-only issues without simulator reproduction, or UI-only debugging.
When should I use this skill?
User debugs iOS leaked objects, retain cycles, memory growth, or needs memgraph before-after evidence.
What you get
Memgraph captures, leak summaries, ownership traces, and before-after proof of disappeared leaked types.
Files
iOS Memgraph Leaks
Use this skill to prove iOS leaks from a live simulator process or an existing .memgraph. Pair it with ../ios-debugger-agent/SKILL.md when the task also needs simulator build, install, launch, UI driving, logs, or screenshots.
Core Workflow
1. Build, launch, and drive the exact flow that should release objects. 2. Capture a memgraph from the running simulator process with scripts/capture_sim_memgraph.sh. 3. Summarize leaks with scripts/summarize_memgraph_leaks.py. 4. For each app-owned leaked type, inspect ownership with leaks --traceTree=<address> <file.memgraph> and grouped leak evidence. 5. Make the smallest root-cause patch, then recapture the same flow on the same simulator when possible. 6. Report proof: before/after leak counts, disappeared root types, remaining leaks, memgraph paths, and test/build results.
Do not claim a leak fix from a smaller memgraph alone. A credible fix explains the ownership path that kept the object alive and shows that the same path or type disappears after the patch.
Capture
Prefer capturing from the simulator already used for the reproduction. Resolve the simulator UDID and app bundle identifier, then capture the running app:
SKILL_DIR="<absolute path to this loaded skill folder>"
SIM="<simulator-udid>"
BUNDLE_ID="<app.bundle.identifier>"
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"Do not derive SKILL_DIR from the target app repo's pwd; installed plugins usually live outside the app being debugged. Store captures in a run-specific temp or user-chosen folder, not under SKILL_DIR.
If the process cannot be found, confirm the bundle identifier and use xcrun simctl spawn "$SIM" launchctl list to inspect running labels.
Summarize
Summarize an existing memgraph:
"$SKILL_DIR/scripts/summarize_memgraph_leaks.py" \
/path/to/app.memgraph \
--trace-limit 5 \
--out /path/to/leak-summary.mdUse --trace-limit sparingly. Trace trees are useful root-cause evidence, but large memgraphs can produce noisy output. If a trace tree says Found 0 roots referencing, treat it as an unreachable/self-retained leak candidate and use the summary's grouped leak tree or leaks --groupByType <file.memgraph> to identify the retained fields and payload chain.
Root Cause Rules
- Identify the first app-owned leaked type in the leak output or trace.
- Determine the intended lifetime: process, session, account, view, request, or task.
- Treat lazy or deferred allocation as a scope reduction, not a leak fix, unless the original eager allocation itself violated the intended lifetime.
- Prove retain-cycle claims with either a
traceTreeownership path or an isolated reproduction. - For unreachable/self-cycle leaks,
traceTreemay have no root path; useleaks --groupByTypeplus source verification to find the self-retaining edge. - Do not claim success just because total leak count went down; prove the specific type or path disappeared.
- Separate real root-cause branches from candidate/noise branches.
- Prefer deleting the retaining edge over adding broad cleanup code.
Report
A useful leak report includes:
- the exact flow and simulator/app build
- the memgraph and summary paths
- app-owned leaked types and counts
- at least one ownership path, or grouped leak tree evidence when the object is unreachable from roots
- the smallest proposed or applied retaining-edge fix
- before/after evidence when a fix was made
If the memgraph shows only framework/runtime noise, say that and recommend the next narrower capture rather than inventing an app leak.
interface:
display_name: "iOS Memgraph Leaks"
short_description: "Capture and prove iOS simulator memory leaks"
default_prompt: "Use $ios-memgraph-leaks to capture an iOS simulator memgraph, identify retention paths, and verify leak fixes."
#!/usr/bin/env bash
set -euo pipefail
usage() {
cat <<'USAGE'
Capture a memory graph from a running iOS simulator app.
Required:
--udid UDID Simulator UDID
--bundle-id ID App bundle identifier, e.g. com.example.app
Optional:
--out-dir DIR Output directory for the memgraph and leaks output
Example:
capture_sim_memgraph.sh --udid "$SIM" --bundle-id com.example.app --out-dir /tmp/codex-ios-memgraph
USAGE
}
require_value() {
local flag="$1"
local value="${2:-}"
if [[ -z "$value" ]]; then
echo "$flag requires a value" >&2
usage >&2
exit 2
fi
}
bundle_id=""
out_dir=""
udid=""
while [[ $# -gt 0 ]]; do
case "$1" in
--bundle-id)
require_value "$1" "${2:-}"
bundle_id="$2"
shift 2
;;
--out-dir)
require_value "$1" "${2:-}"
out_dir="$2"
shift 2
;;
--udid)
require_value "$1" "${2:-}"
udid="$2"
shift 2
;;
-h|--help)
usage
exit 0
;;
*)
echo "Unknown argument: $1" >&2
usage >&2
exit 2
;;
esac
done
if [[ -z "$udid" ]]; then
echo "--udid is required" >&2
usage >&2
exit 2
fi
if [[ -z "$bundle_id" ]]; then
echo "--bundle-id is required" >&2
usage >&2
exit 2
fi
if [[ -z "$out_dir" ]]; then
out_dir="$(mktemp -d "${TMPDIR:-/tmp}/codex-ios-memgraph.XXXXXX")"
fi
matching_processes="$(
xcrun simctl spawn "$udid" launchctl list |
awk -v bundle_id="$bundle_id" '
$1 == "-" {
next
}
$3 == bundle_id {
print $1 "\t" $3
next
}
index($3, "UIKitApplication:" bundle_id "[") == 1 {
print $1 "\t" $3
}
'
)"
if [[ -z "$matching_processes" ]]; then
echo "Could not find a running PID for $bundle_id on $udid" >&2
exit 1
fi
if [[ "$(printf '%s\n' "$matching_processes" | wc -l | tr -d ' ')" -ne 1 ]]; then
echo "Found multiple running PIDs for $bundle_id on $udid:" >&2
printf '%s\n' "$matching_processes" >&2
exit 1
fi
pid="$(printf '%s\n' "$matching_processes" | awk '{ print $1 }')"
process_label="$(printf '%s\n' "$matching_processes" | cut -f2-)"
mkdir -p "$out_dir"
timestamp="$(date +%Y%m%d-%H%M%S)"
safe_bundle="$(printf '%s' "$bundle_id" | tr -c 'A-Za-z0-9_.-' '_')"
memgraph="$out_dir/$safe_bundle-$pid-$timestamp.memgraph"
leaks_output="$out_dir/$safe_bundle-$pid-$timestamp.leaks.txt"
metadata="$out_dir/$safe_bundle-$pid-$timestamp.metadata.txt"
{
echo "date: $(date)"
echo "udid: $udid"
echo "bundle_id: $bundle_id"
echo "process_label: $process_label"
echo "pid: $pid"
echo "memgraph: $memgraph"
echo "leaks_output: $leaks_output"
} > "$metadata"
set +e
leaks "--outputGraph=$memgraph" "$pid" > "$leaks_output" 2>&1
leaks_status=$?
set -e
echo "leaks_exit_status: $leaks_status" >> "$metadata"
if [[ ! -f "$memgraph" ]]; then
echo "memgraph_missing: true" >> "$metadata"
echo "leaks failed to create a memgraph; see: $leaks_output" >&2
echo "metadata: $metadata" >&2
exit 1
fi
echo "memgraph: $memgraph"
echo "leaks output: $leaks_output"
echo "metadata: $metadata"
#!/usr/bin/env python3
"""Summarize leaks output from an Apple .memgraph file."""
from __future__ import annotations
import argparse
import re
import subprocess
import sys
from collections import Counter
from pathlib import Path
LEAK_RE = re.compile(r"^Leak:\s+(?P<address>0x[0-9a-fA-F]+)\s+size=(?P<size>\d+)\s+(?P<rest>.*)$")
TOTAL_RE = re.compile(r"Process\s+\S+:\s+(?P<count>\d+)\s+leaks?\s+for\s+(?P<bytes>\d+)\s+total leaked bytes")
def run_leaks(args: list[str]) -> subprocess.CompletedProcess[str]:
return subprocess.run(["leaks", *args], text=True, capture_output=True, check=False)
def parse_leaks(output: str) -> tuple[str | None, list[dict[str, str]]]:
total = None
leaks: list[dict[str, str]] = []
for line in output.splitlines():
if total is None:
match = TOTAL_RE.search(line)
if match:
total = f"{match.group('count')} leaks / {match.group('bytes')} bytes"
match = LEAK_RE.match(line)
if match:
fields = match.groupdict()
rest = fields.pop("rest")
rest = re.sub(r"^zone:\s+\S+\s+", "", rest)
parts = re.split(r"\s{2,}", rest.strip(), maxsplit=2)
if len(parts) == 3:
fields["type"], fields["language"], fields["image"] = parts
elif len(parts) == 2:
fields["type"], fields["image"] = parts
fields["language"] = "<unknown>"
else:
fields["type"] = rest.strip() or "<unknown>"
fields["language"] = "<unknown>"
fields["image"] = "<unknown>"
leaks.append(fields)
return total, leaks
def trace_excerpt(memgraph: Path, address: str, max_lines: int) -> str:
result = run_leaks([f"--traceTree={address}", str(memgraph)])
text = result.stdout or result.stderr
lines = [line.rstrip() for line in text.splitlines() if line.strip()]
return "\n".join(lines[:max_lines])
def group_by_type_excerpt(memgraph: Path, max_lines: int) -> str:
result = run_leaks(["--groupByType", str(memgraph)])
text = result.stdout or result.stderr
lines = [line.rstrip() for line in text.splitlines() if line.strip()]
return "\n".join(lines[:max_lines])
def render(memgraph: Path, trace_limit: int, trace_lines: int, raw_output: str) -> str:
total, leaks = parse_leaks(raw_output)
by_type = Counter(leak["type"] for leak in leaks)
by_image = Counter(leak["image"] for leak in leaks)
lines: list[str] = []
lines.append(f"# Leak Summary: {memgraph}")
lines.append("")
lines.append(f"- Total: {total or 'not found'}")
lines.append(f"- Parsed leak entries: {len(leaks)}")
lines.append("")
if by_type:
lines.append("## Top Types")
for name, count in by_type.most_common(20):
lines.append(f"- {count}x {name}")
lines.append("")
if by_image:
lines.append("## Top Images")
for name, count in by_image.most_common(20):
lines.append(f"- {count}x {name}")
lines.append("")
if leaks:
lines.append("## Leak Entries")
for leak in leaks[:50]:
lines.append(
f"- {leak['address']} size={leak['size']} type={leak['type']} "
f"image={leak['image']}"
)
if len(leaks) > 50:
lines.append(f"- ... {len(leaks) - 50} more")
lines.append("")
if trace_limit > 0 and leaks:
lines.append("## TraceTree Excerpts")
for leak in leaks[:trace_limit]:
lines.append(f"### {leak['address']} {leak['type']}")
excerpt = trace_excerpt(memgraph, leak["address"], trace_lines)
lines.append("~~~text")
lines.append(excerpt or "<no trace output>")
lines.append("~~~")
lines.append("")
if leaks:
lines.append("## Grouped Leak Tree")
lines.append("Use this when `traceTree` has no roots, which is common for unreachable retain cycles.")
lines.append("~~~text")
lines.append(group_by_type_excerpt(memgraph, trace_lines) or "<no grouped leak output>")
lines.append("~~~")
lines.append("")
lines.append("## Raw Commands")
lines.append("~~~bash")
lines.append(f"leaks --list {memgraph}")
if leaks:
lines.append(f"leaks --groupByType {memgraph}")
if leaks:
lines.append(f"leaks --traceTree={leaks[0]['address']} {memgraph}")
lines.append("~~~")
lines.append("")
return "\n".join(lines)
def main() -> int:
parser = argparse.ArgumentParser(description=__doc__)
parser.add_argument("memgraph", type=Path)
parser.add_argument("--trace-limit", type=int, default=0, help="Number of leaks to trace with --traceTree")
parser.add_argument("--trace-lines", type=int, default=80, help="Max lines per traceTree excerpt")
parser.add_argument("--out", type=Path, help="Write markdown summary to this file")
args = parser.parse_args()
if not args.memgraph.exists():
print(f"memgraph not found: {args.memgraph}", file=sys.stderr)
return 2
result = run_leaks(["--list", str(args.memgraph)])
raw = result.stdout or result.stderr
total, leaks = parse_leaks(raw)
if result.returncode != 0 and total is None and not leaks:
print(raw, file=sys.stderr, end="" if raw.endswith("\n") else "\n")
return result.returncode or 1
summary = render(args.memgraph, args.trace_limit, args.trace_lines, raw)
if args.out:
args.out.parent.mkdir(parents=True, exist_ok=True)
args.out.write_text(summary)
print(args.out)
else:
print(summary)
return 0
if __name__ == "__main__":
raise SystemExit(main())
Related skills
FAQ
What does ios-memgraph-leaks produce?
Simulator memgraph captures, leak summaries, ownership traces, and before-after leak count proof.
When should I use ios-memgraph-leaks?
When proving iOS simulator memory leaks and validating the smallest retaining-edge fix.
Is ios-memgraph-leaks safe to install?
Review the Security Audits panel on this page before installing in production.