One-Page Constraints Sheet

The one-page constraints sheet is a single document that captures six decisions every design project needs before pixels move. It names one human decider whose signature binds the work. It defines done as a specific artifact such as a deployed URL with 12 live pages a Figma library of 24 components and Core Web Vitals scores above 90. It lists every out-of-scope item such as no new motion assets no CRM hooks and no extra localizations after week three. It states the sold price and the kill price 20 percent higher that stops all work when crossed. It pins a ship date and a kill date tied to real events like a funding announcement or conference launch. It declares the one metric such as qualified leads per month or support tickets dropped from 47 to 12 measured by a named tool and reviewed on a fixed schedule. Fill it live in the first meeting read it aloud get the signature and attach it to the contract. It becomes the project constitution consulted whenever drift appears.

This sheet is not a 30-slide deck stuffed with mood boards coral check marks and adjectives like modern or delightful. It is not a committee-produced wish list that says the leadership team will weigh in or we will know it when we see it. It is not buried in a Notion database or padded with supporting research that nobody reads after kickoff. Those versions are theater. They let everyone feel aligned until week six when the client requests one more round the budget quietly expands and the agency eats the overrun because there is no kill number on paper. The sheet rejects all of it. No ranges. No vibes. No escape clauses that let scope creep walk in the back door while everyone stays polite.

Look at the 2024 Brainy Papers glossary site rebuild. The sheet listed Senior Editor as decider with zero consulted names. Done meant 15 published terms at papers.brainy.ink a live component library and lighthouse scores over 95. Out of scope blocked new illustration directions CRM integrations and any work past the kill date. Sold at 26k kill at 32k. Ship date March 12 kill date March 28 tied to the quarterly planning review. The one metric was glossary lookups rising from 4100 to 7500 per week tracked in Plausible and reviewed every Monday. When a late request for video embeds arrived we opened the sheet pointed at the out-of-scope line triggered the written change order rule and kept the project on budget. The same discipline appeared in Stripe's 2022 billing portal refresh where the sheet locked conversion rate on checkout as the metric refused abandoned-cart scope and used a rigid kill date tied to their product summit. Vercel applied it to their 2023 docs overhaul. Done was every feature launch including its deploy log as the hero surface. The metric was time from signup to first successful deployment dropping from 68 seconds to 21 seconds. The out-of-scope list killed three nice-to-have illustration packages that would have doubled the timeline. A Linear-modeled startup in early 2025 used theirs for a six-week command-bar cycle. Decider was the PM. Done was six shipped issues with updated help docs. The metric was tasks completed per user per week. When the decider swapped mid-project the kill criteria forced a re-signature within five days or work paused. That sheet killed two feature requests before they could metastasize.

Use the sheet at the first client meeting for any engagement over two weeks or 10k. Bring the blank template push for concrete numbers while optimism is high and watch who squirms at naming a single decider or writing a kill date. It filters clients who prefer theater before hours are burned. Deploy it for full site launches brand refreshes and SaaS feature builds where scope creep loves to hide. Customize the kill criteria section to the exact risks of that job. A marketing site adds a trigger around traffic source quality. A product redesign adds one around user testing participation rates. Do not use it for solo side projects internal hack days or one-afternoon headline fixes. Those have near-zero drift cost and the overhead of signatures adds friction that slows momentum. Never treat the sheet as boilerplate sales decoration. It only works when filled together argued over and signed while the discomfort is fresh.

The one-page constraints sheet turns hope into hardware before the first pixel drops.