ui-extensions-sdk CLAUDE.md

ui-extensions-sdk CLAUDE.md is an instructions file for coding agents from contentful/ui-extensions-sdk. It costs 804 tokens per session, scanned A, original, MIT.

Repository guidance for Contentful's TypeScript App SDK, a library that lets customer-built apps extend the Contentful content platform.

In plain words
What is it for?
Use it when changing public types or modules, adding tests, reviewing dependencies, preparing commits, or making a release-safe API change.
Why use it?
It explains the public API rules, ownership, testing, dependency, versioning, and review constraints that protect users of the published package.

Instructions file

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 instructions/contentful/ui-extensions-sdk/claude-md
Clone the repo
git clone --depth 1 https://github.com/contentful/ui-extensions-sdk

Wrote 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.

agentmods badge for ui-extensions-sdk CLAUDE.md

README.md
[![agentmods](https://agentmods.dev/badge/instructions/contentful/ui-extensions-sdk/claude-md.svg)](https://agentmods.dev/instructions/contentful/ui-extensions-sdk/claude-md)
Your own site
<a href="https://agentmods.dev/instructions/contentful/ui-extensions-sdk/claude-md"><img src="https://agentmods.dev/badge/instructions/contentful/ui-extensions-sdk/claude-md.svg" alt="Measured on agentmods" height="20"></a>
Per session 804 This file is loaded in full into every session.
When invoked 804 The same file — it is already loaded in full.
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 $0.00804 $0.00804
Opus 5 $0.00402 $0.00402
Sonnet 5 $0.00161 $0.00161
Haiku 4.5 $0.00080 $0.00080

Measured 4d ago against content hash 0d3477ff3f06, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

ui-extensions-sdk CLAUDE.md 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 4d 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.

CLAUDE.md · 61 lines

How it starts

The opening of the file, as written. The whole thing — 61 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Claude Project Instructions — ui-extensions-sdk

You are working in the ui-extensions-sdk repo (github.com/contentful/ui-extensions-sdk). It builds the App SDK and publishes it to npm as @contentful/app-sdk (preferred) and the legacy contentful-ui-extensions-sdk alias. Read AGENTS.md and ARCHITECTURE.md before making non-trivial changes.

Identity & Scope

  • This is a public, customer-facing TypeScript library. Public types are a contract: thousands of customer apps and many internal repos consume lib/types/index.ts.
  • Co-owned by @contentful/team-extensibility and @contentful/team-marketplace.
  • Bundle size is policed by CI. Adding a runtime dependency is almost always wrong — contentful-management is currently the only one.

Working style

  • Conventional Commits at PR-title level. Use feat:, fix:, chore: (no release), docs: (no release), refactor: (no release).
  • Breaking changes require a BREAKING CHANGE: footer — feat!: alone does not bump major reliably.
  • One unit test per module under test/unit/<module>.spec.ts.
  • No any in public types. unknown is acceptable internally.
  • Squash merge. PR title becomes the commit message.

Sharp edges

  1. Do not edit package.json#namescripts/publish.js mutates it during dual-publish.
  2. Do not add methods to lib/space.ts — it is deprecated since v4.0.0.
  3. Do not reference globalThis.contentfulExtension in new code; it's a back-compat alias only.
  4. Do not run npm install if you don't have to — npm ci is the source of truth and CI uses it.
  5. Do not skip the husky pre-commit hook with --no-verify unless the hook itself is broken.
  6. Do not introduce ESM-only dependencies — the bundle is UMD-target ES5.

Verification before claiming done

npm run check-types
npm run lint
npm test
npm run build
npm run size

If any of these fail, the work is not done. Fix the root cause; do not bypass.

Read the full file on GitHub · 61 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. 4d ago First seen · 61 lines · 804 tokens per session scan A 0d3477ff3f06

Subscribe to this mod's changes

ui-extensions-sdk CLAUDE.md is an instructions file published in the GitHub repository contentful/ui-extensions-sdk (131 stars, last pushed 5d ago), licensed MIT. It adds 804 tokens to every session, about $0.0040 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 2026-08-30.