asc-performance

Original：🇺🇸 English

Translated

Manage power and performance metrics and diagnostic logs using the `asc` CLI tool. Use this skill when: (1) Listing performance metrics for an app: "asc perf-metrics list --app-id <id>" (2) Listing performance metrics for a build: "asc perf-metrics list --build-id <id>" (3) Filtering metrics by type: "asc perf-metrics list --app-id <id> --metric-type LAUNCH" (4) Listing diagnostic signatures for a build: "asc diagnostics list --build-id <id>" (5) Filtering diagnostics: "asc diagnostics list --build-id <id> --diagnostic-type HANGS" (6) Viewing diagnostic logs: "asc diagnostic-logs list --signature-id <id>" Also trigger when the user mentions: performance metrics, launch time, hang rate, disk writes, memory usage, battery life, termination, animation hitches, diagnostic signatures, call stacks, power metrics, app performance monitoring, "why is my app slow", "check hangs", "check launch time"

2installs

Sourcetddworks/asc-cli-skills

Added on2026-03-14

NPX Install

npx skill4agent add tddworks/asc-cli-skills asc-performance

SKILL.md Content

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Power & Performance with

asc

Download performance metrics and diagnostic logs to monitor app performance indicators — launch time, hang rate, disk writes, memory use, battery life, termination, and animation hitches.

Authentication

bash

asc auth login --key-id <id> --issuer-id <id> --private-key-path ~/.asc/AuthKey.p8

How to Navigate (CAEOAS Affordances)

Every JSON response contains an

"affordances"

field with ready-to-run commands — IDs already filled in. Follow the affordances to drill down from metrics to diagnostics to logs.

App metrics → Diagnostics → Logs flow:

json

// 1. asc perf-metrics list --app-id app-1 → shows performance overview
{
  "id": "app-1-LAUNCH-launchTime",
  "category": "LAUNCH",
  "latestValue": 1.5,
  "affordances": {
    "listAppMetrics": "asc perf-metrics list --app-id app-1"
  }
}

// 2. asc diagnostics list --build-id build-1 → shows hotspots
{
  "id": "sig-1",
  "diagnosticType": "HANGS",
  "weight": 45.2,
  "affordances": {
    "listLogs": "asc diagnostic-logs list --signature-id sig-1",
    "listSignatures": "asc diagnostics list --build-id build-1"
  }
}

// 3. asc diagnostic-logs list --signature-id sig-1 → shows call stacks
{
  "id": "sig-1-0-0",
  "bundleId": "com.example.app",
  "callStackSummary": "main > UIKit > layoutSubviews",
  "affordances": {
    "listLogs": "asc diagnostic-logs list --signature-id sig-1"
  }
}

Typical Workflows

Check app performance at a glance

bash

asc perf-metrics list --app-id 123456789 --pretty

Investigate a specific metric type

bash

# Launch time only
asc perf-metrics list --app-id 123456789 --metric-type LAUNCH --pretty

# Hang rate only
asc perf-metrics list --app-id 123456789 --metric-type HANG --pretty

Compare build-specific metrics

bash

asc builds list --app-id 123456789 --output table
asc perf-metrics list --build-id build-abc --pretty

Diagnose hangs in a build

bash

# 1. List diagnostic signatures (hang hotspots)
asc diagnostics list --build-id build-abc --diagnostic-type HANGS --pretty

# 2. Drill into the top signature's call stacks
asc diagnostic-logs list --signature-id sig-1 --pretty

Full investigation pipeline

bash

# Start from builds
BUILD_ID=$(asc builds list --app-id APP_ID | jq -r '.data[0].id')

# Check performance metrics
asc perf-metrics list --build-id "$BUILD_ID" --pretty

# Find hang hotspots
asc diagnostics list --build-id "$BUILD_ID" --diagnostic-type HANGS --pretty

# Get call stacks for the heaviest signature
SIG_ID=$(asc diagnostics list --build-id "$BUILD_ID" --diagnostic-type HANGS \
  | jq -r '.data | sort_by(-.weight) | .[0].id')
asc diagnostic-logs list --signature-id "$SIG_ID" --pretty

Performance Metric Categories

Category	`--metric-type` value	What it measures
Launch	`LAUNCH`	App launch time
Hang	`HANG`	Main thread hang rate
Memory	`MEMORY`	Peak and average memory use
Disk	`DISK`	Disk write volume
Battery	`BATTERY`	Energy impact
Termination	`TERMINATION`	Background/foreground terminations
Animation	`ANIMATION`	Animation hitch rate

Diagnostic Types

Type	`--diagnostic-type` value	What it captures
Hangs	`HANGS`	Main thread hang signatures
Disk Writes	`DISK_WRITES`	Excessive disk write signatures
Launches	`LAUNCHES`	Slow launch signatures

Reading Results

PerformanceMetric — one row per metric identifier (e.g.

launchTime

,

peakMemory

), flattened from the nested Xcode Metrics API. Key fields:

```
category
```
— which metric group (LAUNCH, HANG, etc.)
```
latestValue
```
+
```
unit
```
— most recent measurement
```
goalValue
```
— Apple's recommended target
```
parentType
```
—
```
"app"
```
or
```
"build"
```
(tells you whether this came from app-level or build-level metrics)

DiagnosticSignatureInfo — a recurring issue pattern ranked by

weight

(% of occurrences). Higher weight = more impactful.

insightDirection

of

"UP"

means the issue is getting worse.

DiagnosticLogEntry — individual log with device metadata and

callStackSummary

(top 5 frames joined with

).

Full Command Reference

See commands.md for all flags and examples.

asc-performance

NPX Install

Tags

SKILL.md Content

Power & Performance with
`asc`

Authentication

How to Navigate (CAEOAS Affordances)

Typical Workflows

Check app performance at a glance

Investigate a specific metric type

Compare build-specific metrics

Diagnose hangs in a build

Full investigation pipeline

Performance Metric Categories

Diagnostic Types

Reading Results

Full Command Reference