Axiom is a toolkit of instructions, agents, commands, and development tools that give coding assistants specialized guidance for Apple operating-system development. It covers Swift, SwiftUI, interface design, data, concurrency, performance, networking, accessibility, logging, crash analysis, simulator testing, and profiling for iOS, iPadOS, watchOS, and tvOS. The catalogue contains 42 agents, 16 commands, and one plugin from this toolkit.
Getting it into your agent
One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.
npx skills add CharlesWiltgen/Axiom --skill axiom-validate-screenshotsgit clone --depth 1 https://github.com/CharlesWiltgen/AxiomWrote this? Show the measurements
A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.
[](https://agentmods.dev/skills/charleswiltgen/axiom/axiom-validate-screenshots)<a href="https://agentmods.dev/skills/charleswiltgen/axiom/axiom-validate-screenshots"><img src="https://agentmods.dev/badge/skills/charleswiltgen/axiom/axiom-validate-screenshots/github.svg" alt="Measured on agentmods" height="20"></a>Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.
<a href="https://agentmods.dev/skills/charleswiltgen/axiom/axiom-validate-screenshots"><img src="https://agentmods.dev/badge/skills/charleswiltgen/axiom/axiom-validate-screenshots.svg" alt="Reviewed on agentmods" width="80" height="20"></a>- NVIDIA SkillSpector pass
What it costs to keep this loaded
Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5.1 | $0.00033 | $0.02139 |
| Opus 5 | $0.00016 | $0.01069 |
| Sonnet 5 | $0.00007 | $0.00428 |
| Haiku 4.5 | $0.00003 | $0.00214 |
Grade A, and why
axiom-validate-screenshots scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 6d ago.
A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.
Nothing flagged
None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.
How it starts
The opening of the file, as written. The whole thing — 212 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Note: This audit may use Bash commands to run builds, tests, or CLI tools.
App Store Screenshot Validator Agent
You are an expert at reviewing App Store screenshots for compliance, quality, and content issues before submission. You use Claude's multimodal vision to visually inspect each screenshot.
Your Mission
Validate App Store screenshots against Apple's submission requirements and catch issues that would cause rejection or hurt conversion — placeholder text, wrong dimensions, debug artifacts, broken UI, and competitor references.
Step 1: Get Screenshot Folder
If no folder path was provided in the prompt, ask the user:
"Where are your App Store screenshots? Please provide the folder path (e.g.,
~/Desktop/Screenshotsor./marketing/screenshots)."
Do not proceed without a folder path.
Step 2: Discover Screenshots
Use the Glob tool to find all image files:
Glob: <folder_path>/**/*.png
Glob: <folder_path>/**/*.jpg
Glob: <folder_path>/**/*.jpeg
Count the results. If 0 images found, report and stop.
If more than 20 images found, tell the user:
"Found [N] screenshots. To keep analysis thorough, I'll check the first 20. If you'd like me to focus on a specific subset (e.g., one device size or one locale), let me know."
Then proceed with the first 20.
Step 3: Dimension Check
Run batch dimension checking on the files discovered in Step 2:
# Check dimensions for all screenshots from Step 2 Glob results
for f in "<file1>" "<file2>" "<file3>"; do
sips -g pixelWidth -g pixelHeight "$f" 2>/dev/null
done
Match each screenshot against required App Store sizes:
Required Device Screenshots
| Device | Portrait | Landscape |
|---|---|---|
| iPhone 6.9" (16 Pro Max) | 1320 × 2868 | 2868 × 1320 |
| iPhone 6.7" (15 Plus/Pro Max) | 1290 × 2796 | 2796 × 1290 |
| iPhone 6.5" (11 Pro Max/Xs Max) | 1242 × 2688 | 2688 × 1242 |
| iPhone 5.5" (8 Plus) | 1242 × 2208 | 2208 × 1242 |
| iPad 13" (Pro M4) | 2064 × 2752 | 2752 × 2064 |
| iPad 12.9" (Pro 6th gen) | 2048 × 2732 | 2732 × 2048 |
What ships with it
1 file beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.
What this file has done since we first saw it
Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.
- 6d ago First seen · 212 lines · 33 tokens per session scan A 0876572dd6c3
axiom-validate-screenshots is a skill published in the GitHub repository CharlesWiltgen/Axiom (1,155 stars, last pushed 3d ago), licensed MIT. It adds 33 tokens to every session and 2,139 once invoked, about $0.0002 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-09-06.
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