designer-frontend-contract

designer-frontend-contract is a skill for Claude Code, Codex from endorphin-ai/hasbrains-agent-kit. It costs 294 tokens per session (2,749 once invoked), scanned A, original, MIT.

A set of rules for designers and frontend developers to share approved designs, implementation files, and checks. It defines how a design becomes a working webpage and how the result is compared with the approved design.

In plain words
What is it for?
Use it to organize designer-developer handoffs, store shared design references, implement pages from approved mockups, and verify the running interface against those mockups.
Why use it?
It prevents developers from silently changing the design, leaving out page sections, or shipping a broken interface that basic website checks do not catch.

Skill for Claude CodeCodex

Written for no agent in particular: nothing here depends on one.

Part of the web-dev plugin — 2 skills shipped together

Good fit Use it to organize designer-developer handoffs, store shared design references, implement pages from approved mockups, and verify the running interface against those mockups.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/endorphin-ai/hasbrains-agent-kit/designer-frontend-contract
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.

Any agent
npx skills add endorphin-ai/hasbrains-agent-kit --skill designer-frontend-contract
Clone the repo
git clone --depth 1 https://github.com/endorphin-ai/hasbrains-agent-kit

Made for: Claude Code, Codex.

Or install web-dev, the plugin that ships this one along with the rest of its 2 skills.

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 designer-frontend-contract

README.md
[![agentmods](https://agentmods.dev/badge/skills/endorphin-ai/hasbrains-agent-kit/designer-frontend-contract/github.svg)](https://agentmods.dev/skills/endorphin-ai/hasbrains-agent-kit/designer-frontend-contract)
Your own site
<a href="https://agentmods.dev/skills/endorphin-ai/hasbrains-agent-kit/designer-frontend-contract"><img src="https://agentmods.dev/badge/skills/endorphin-ai/hasbrains-agent-kit/designer-frontend-contract/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.

agentmods 80×15 button for designer-frontend-contract

Your own site · 80×15
<a href="https://agentmods.dev/skills/endorphin-ai/hasbrains-agent-kit/designer-frontend-contract"><img src="https://agentmods.dev/badge/skills/endorphin-ai/hasbrains-agent-kit/designer-frontend-contract.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 294 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 2,749 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.
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 5.1 $0.00294 $0.02749
Opus 5 $0.00147 $0.01375
Sonnet 5 $0.00059 $0.00550
Haiku 4.5 $0.00029 $0.00275

Measured 10d ago against content hash 842086e98865, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-10, from the pricing page.

Security

Grade A, and why

designer-frontend-contract 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 10d 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.

web-dev/skills/designer-frontend-contract/SKILL.md · 151 lines

How it starts

The opening of the file, as written. The whole thing — 151 lines — stays where its author put it; the contents beside it link to each section on GitHub.

TASKLANG TYPE SKILL

IDENTITY "Designer ↔ Frontend Contract (universal — any stack)"

ONE skill = the WHOLE collaboration between the web designer and the frontend dev: what each side PRODUCES for the other, where the shared data is STORED, how they COMMUNICATE (paths + committed artifacts, never chat blobs), and how the CONTRACT between them is written and mechanically ENFORCED. The designer freezes the approved mockup into an ORACLE; the frontend PORTS it 1:1 and self-gates; the independent design-diff VERIFIES the running UI against the oracle and feeds the pipeline's verify gate. TECH-AGNOSTIC by construction: no framework, port, template language, or product fact lives here — those are read from docs/project_config/info.md ({config.frontend_runtime} + {config.spec_path}) at runtime. It exists because builds without this contract silently re-style, drop whole page regions, and ship broken UI that a green HTTP-200 smoke never catches.

This SKILL.md is a MAP. Detail lives in workflows/ (the three role playbooks) + references/ (atomized notes) + maps/ (machine-readable nav). Read this file + maps/index.json to orient, then open ONLY the workflow/note a task needs.


The three sides (who runs what)

Side Role Playbook Runs when
PRODUCER the design owner (skill owner) [[designer-handoff]] An approved mockup must become a build target: freeze → manifest → inventory → token parity → acceptance contract.
CONSUMER the frontend owner [[frontend-port]] Building a page from a frozen oracle: consume the contract → port 1:1 → self-gate census→DOM→pixel → report + KB write-back.
VERIFIER the design owner + whoever runs the verify gate [[design-diff]] Independently verifying built pages against the oracle (pipeline verify gate, fan-out audit finder, or ad-hoc).

Top Rules / Invariants (headlines — detail in references)

Read the full file on GitHub · 151 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. 10d ago First seen · 151 lines · 294 tokens per session scan A 842086e98865

Subscribe to this mod's changes

designer-frontend-contract is a skill published in the GitHub repository endorphin-ai/hasbrains-agent-kit (4 stars, last pushed today), licensed MIT. It adds 294 tokens to every session and 2,749 once invoked, about $0.0015 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 2026-08-31.

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