Designer Frontend Contract
designer-frontend-contract/
Freeze an approved mockup into a reference, port it 1:1 on any stack, and verify every page, state and breakpoint with screenshot diffs before merge.

The tech-agnostic contract between designer and frontend dev, and the gate that mechanically enforces it.
Why use it
- "Matches the design" asserted from a screenshot glance, while a whole page region is missing.
- The build quietly re-styles the mockup, and the drift is only noticed after launch.
- HTTP 200 and a green CI badge say nothing about whether the UI is actually right.
What it does
- Designer side: freeze the approved mockup into a canonical oracle: manifest, baseline renders, a region/element inventory, token parity, a visual acceptance contract.
- Frontend side: port the oracle 1:1 (transcribe, never redesign) and self-gate census → DOM → pixel before handoff.
- Verifier side: independently screenshot every page × access state × pinned breakpoint against the frozen baseline; census FIRST, then pixel diff, then interaction hit-testing.
- Report-only verification: findings route to the dev (drift) or the designer (a legitimate design change).
Benefits
- Ship what was actually designed. Fidelity becomes an enforced gate, not an assumption.
- Catch the missing region the pixel diff would have waved through.
- No more launch-day drift: every page, state and breakpoint is checked before merge.
- Any stack. Dev server, template language and tokens all come from your project config.
Install
Download this skill and copy the designer-frontend-contract folder to .claude/skills/designer-frontend-contract/ in your project, or to ~/.claude/skills/designer-frontend-contract/ to use it in every project. Claude Code finds it on its own; you can also call it with /designer-frontend-contract.
Part of the Web Dev Design Pipeline bundle. To get the whole set as a Claude Code plugin: /plugin marketplace add endorphin-ai/hasbrains-agent-kit, then /plugin install web-dev@hasbrains-agent-kit.
Source: endorphin-ai/hasbrains-agent-kit. License: MIT.
Files (18)
Files
{
"skill": "designer-frontend-contract",
"version": "2.0",
"kind": "second-brain",
"entry": "SKILL.md",
"maps": {
"index": "maps/index.json",
"tags": "maps/tags.json",
"links": "maps/links.json"
},
"companions": [
"FORMAT.md",
"VOICE.md"
],
"workflows": [
"workflows/designer-handoff.md",
"workflows/frontend-port.md",
"workflows/design-diff.md"
],
"references": [
"references/contract-and-communication.md",
"references/region-census.md",
"references/baseline-and-oracle.md",
"references/fidelity-checks.md"
],
"roles": {
"producer_owner": "the design owner",
"verify_path": "whoever runs the verify gate",
"consumer": "the frontend owner"
},
"current_project_bindings": {
"note": "Bind these role slots to the actual agents/roles in YOUR project. The skill body speaks in roles only — retargeting means changing these bindings, never the skill body.",
"owner_agents": [
"<your design agent>"
],
"verify_path_agents": [
"<your verify-gate agent>"
],
"consumer_agents": [
"<your frontend agent>"
]
},
"stack_facts_source": "docs/project_config/info.md#{config.frontend_runtime}",
"note_count": 7,
"generated_by": "claude-fable-5 (designer-frontend-contract unification)"
}