cms-assets

A guide to managing Contentstack images and other media files, including organization, publishing, CDN delivery, and image transformations.

In plain words
What is it for?
Use it to plan asset folders, optimize images with the Image Delivery API, and troubleshoot publishing, replacement, unpublishing, and CDN issues.
Why use it?
It helps prevent broken asset references and unclear delivery behavior while serving appropriately transformed media.

Skill for Claude CodeCodex

Install

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.

agentmods
npx agentmods add skills/contentstack/contentstack-agent-skills/cms-assets
Any agent
npx skills add contentstack/contentstack-agent-skills --skill cms-assets
Clone the repo
git clone --depth 1 https://github.com/contentstack/contentstack-agent-skills

Made for: Claude Code, Codex.

Per session 0 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 980 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
Origin original No closer match found in the catalogue.
Token cost

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.

ModelPer sessionOnce invoked
Fable 5 $0.00000 $0.00980
Opus 5 $0.00000 $0.00490
Sonnet 5 $0.00000 $0.00196
Haiku 4.5 $0.00000 $0.00098

Measured yesterday against content hash a1d7f367a3ba, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

cms-assets 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 yesterday.

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.

codex/cms-assets/SKILL.md · 97 lines

How it starts

The opening of the file, as written. The whole thing — 97 lines — stays where its author put it; the contents beside it link to each section on GitHub.

cms-assets

Contentstack Assets

Description

Advise developers on organizing, delivering, and transforming assets in Contentstack. Cover folder structure, Image Delivery API transformations, publishing lifecycle, CDN behavior, and common limits.

When to Use

Use when developers ask about uploading, organizing, delivering, transforming, publishing, or troubleshooting images and other media files in Contentstack.

User Problem

Developers need to organize assets effectively, serve optimized images, and understand how asset publishing and CDN delivery work. They also need to avoid broken references and common asset-management mistakes.

Success Criteria

Recommend clear folder structures and naming patterns. Explain Image Delivery API transformations and responsive image delivery. Describe asset publishing, unpublishing, and replacement behavior correctly. Call out relevant limits, gotchas, and reference-breaking actions.

Expected Inputs

  • Asset type and use case
  • Image optimization requirements
  • Folder organization needs
  • Publishing or CDN questions

Expected Outputs

  • Folder structure recommendations
  • Image Delivery API transformation guidance
  • Publishing lifecycle explanations
  • Performance optimization tips

Example User Requests

  • How do I serve responsive images from Contentstack?
  • What image transformations does Contentstack support?
  • How should I organize my assets into folders?
  • Does deleting an asset break references in entries?
  • What is the maximum file size I can upload?

Workflow Summary

Identify the asset type and use case. Recommend folder organization if needed. Explain Image Delivery API transforms for images. Describe publishing and CDN behavior. Flag limits, gotchas, and reference risks.

Instructions

[{"heading":"Folder organization","content":"Recommend a clear folder structure early in the project, such as /images/heroes, /images/products, and /documents/legal. Moving assets between folders preserves UIDs and references."},{"heading":"Image Delivery API","content":"Use images.contentstack.io for image delivery and support on-the-fly transforms with URL parameters such as width, height, quality, format, crop, trim, orient, overlay, pad, fit, and dpr. Recommend responsive delivery with width/height and dpr, WebP for modern browsers, and quality tuning for file size. Chain multiple transforms in one URL. Non-image assets serve from assets.contentstack.io."},{"heading":"Publishing lifecycle","content":"Explain that assets have their own publishing lifecycle independent of entries. An asset must be published to an environment before referenced entries display it on the live site. Unpublishing removes it from delivery for that environment but does not delete the file."},{"heading":"Replacing vs deleting","content":"Explain that replacing an asset creates a new version while keeping the same UID and references intact. Deleting an asset breaks all references to it in entries. Advise checking references before deletion."},{"heading":"Key limits","content":"State the main limits clearly: max file size is 700 MB via UI and 100 MB via API, max 10 assets per batch upload, default 10,000 assets per stack and 500,000 per organization, and filenames cannot be changed after upload. Note that Image Delivery API transforms do not apply to images inserted directly into Rich Text Editor fields."}],

Read the full file on GitHub · 97 lines

Changes

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.

  1. yesterday First seen · 97 lines · 0 tokens per session scan A a1d7f367a3ba

Subscribe to this mod's changes

cms-assets is a skill published in the GitHub repository contentstack/contentstack-agent-skills (5 stars, last pushed 15d ago), licensed MIT. It costs nothing until one of its globs matches a file; then it loads 980 tokens. 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 2026-08-31.

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