Backend
Backend: Design reliable server behavior around validated inputs and failure paths. Review the repository, browser targets, user flow, route contract, and accessibility needs and produce a backend change with API contract and error cases.
--- name: web-development-backend description: Use for backend when asked to design reliable server behavior around validated inputs and failure paths; produce a backend change with API contract and error cases. license: MIT metadata: author: Thrive category: web-development --- # Backend ## When to use Use this skill for backend when you need to design reliable server behavior around validated inputs and failure paths. The expected result is a backend change with API contract and error cases. ## Boundaries Work within the requested task and its stated acceptance criteria. Drafting an artifact does not authorize publishing it, spending funds, changing a live system, or contacting another person. Identify any such action separately before taking it. ## Inputs Inspect the repository, browser targets, user flow, route contract, and accessibility needs. Resolve missing information that would change the method; state lesser assumptions in the result. ## Method 1. **Diagnose.** Trace a user action through route, component state, request, response, and rendered result. Mark authentication and cache boundaries. 2. **Decide.** Choose a small, testable implementation that covers loading, empty, error, and success states. 3. **Produce.** Build a backend change with API contract and error cases from the inspected material; keep assumptions distinguishable from observed facts. ## Decision rules - Implement normal, loading, empty, error, and retry states. Preserve semantics and keyboard operation before visual polish. - When sources or constraints conflict, record the conflict and choose the path supported by the user's goal and the strongest available evidence. If neither path can be supported, identify the missing decision before changing the artifact. ## Domain rules - Keep markup semantic, interactions keyboard accessible, and client boundaries deliberate. - Check network errors, caching, and input validation where the interface crosses an API. ## Verification Test valid, invalid, and unauthorized requests. Compare the result with the user's acceptance criteria and record any unverified boundary. Show changed routes and components, contract examples, responsive checks, and one browser-level failure test. ## Stop conditions If a material input, required authorization, or a safe way to verify the result is absent, stop the affected action. Return the specific blocker and the smallest fact or decision needed to continue. Do not report an unrun check as passed. ## Output Provide a backend change with API contract and error cases. Include the decisive evidence and actual verification result. Name any artifact location and unresolved issue that affects its use. <!-- MIT License Copyright (c) 2026 Thrive Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions: The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software. THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. -->