Borrowing it
Nothing to install: this file belongs to contentful/ui-extensions-sdk. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.
curl -O https://raw.githubusercontent.com/contentful/ui-extensions-sdk/main/CLAUDE.mdgit clone --depth 1 https://github.com/contentful/ui-extensions-sdkWrote 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/instructions/contentful/ui-extensions-sdk/claude-md)<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/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/instructions/contentful/ui-extensions-sdk/claude-md"><img src="https://agentmods.dev/badge/instructions/contentful/ui-extensions-sdk/claude-md.svg" alt="Reviewed on agentmods" width="80" height="20"></a>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 | $0.00797 | $0.00797 |
| Opus 5.5 | $0.00319 | $0.00319 |
| Sonnet 5.5 | $0.00159 | $0.00159 |
| Haiku 4.5 | $0.00080 | $0.00080 |
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 1mo 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 — 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/group-applied-ai-solutions. - Bundle size is policed by CI. Adding a runtime dependency is almost always wrong —
contentful-managementis 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
anyin public types.unknownis acceptable internally. - Squash merge. PR title becomes the commit message.
Sharp edges
- Do not edit
package.json#name—scripts/publish.jsmutates it during dual-publish. - Do not add methods to
lib/space.ts— it is deprecated since v4.0.0. - Do not reference
globalThis.contentfulExtensionin new code; it's a back-compat alias only. - Do not run
npm installif you don't have to —npm ciis the source of truth and CI uses it. - Do not skip the husky pre-commit hook with
--no-verifyunless the hook itself is broken. - 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.
When adding a new location
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.
- 1mo ago Changed · -7 tokens per session 5290130e652c
- 2mo ago First seen · 61 lines · 804 tokens per session scan A 0d3477ff3f06
ui-extensions-sdk CLAUDE.md is an instructions file published in the GitHub repository contentful/ui-extensions-sdk (131 stars, last pushed 3d ago), licensed MIT. It adds 797 tokens to every session, about $0.0032 per session on Opus 5.5. 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.
ui-extensions-sdk CLAUDE.md compared with instructions from other repositories
| Mod | Type | Stars | Last push | Licence | Scan | Tokens | Works with |
|---|---|---|---|---|---|---|---|
| ui-extensions-sdk CLAUDE.mdcontentful/ui-extensions-sdk | Instructions file | 131 | 3d ago | MIT | A | 797 | Claude Code |
| vscode buildNext.instructions.mdmicrosoft/vscode | Instructions file | 195k | yesterday | MIT | A | 9,719 | GitHub Copilot |
| next.js AGENTS.mdvercel/next.js | Instructions file | 143k | yesterday | MIT | A | 7,461 | Codex, OpenCode |
| langchain AGENTS.mdlangchain-ai/langchain | Instructions file | 149k | yesterday | MIT | A | 4,680 | Codex, OpenCode |
| vscode oss-third-party-notices.instructions.mdmicrosoft/vscode | Instructions file | 195k | yesterday | MIT | A | 5,516 | GitHub Copilot |
| vscode copilot-instructions.mdmicrosoft/vscode | Instructions file | 195k | yesterday | MIT | A | 3,093 | GitHub Copilot |
| deepseek-harness AGENTS.mddeepseek-ai/deepseek-harness | Instructions file | 274k | 2d ago | MIT | A | 4,313 | Codex, OpenCode |