メニュー
Resolves browser CORS errors by identifying missing headers and applying server-side fixes. Do NOT use for authentication errors, API gateway config, or network firewalls.
Codex または Claude でインストール この Prompt をコピーして Codex、Claude、または他のアシスタントに貼り付けると、Skill ページを確認してインストールできます。
SOC 職業分類に基づく
| name | cors-error-resolution |
| description | Resolves browser CORS errors by identifying missing headers and applying server-side fixes. Do NOT use for authentication errors, API gateway config, or network firewalls. |
| version | 1.1.0 |
| time_saved | Manual: 30-90m | With skill: 5-15m |
| license | Proprietary — Personal Use Only |
| category | debugging |
| complexity | Intermediate |
| tokens | ~3500 |
| tags | ["cors","cross-origin","headers","browser","debugging","http"] |
| author | vheins |
Diagnose browser CORS violations and provide server-side configuration fixes for headers and preflight handling.
| Variable | Type | Req | Description |
|---|---|---|---|
tech_stack | string | Yes | e.g., "Node.js + Express" |
error_message | string | Yes | Full browser error message |
request_details | string | Yes | Method, URL, headers, and origin |
server_config | string | No | Current middleware/config |
Allow-Origin, mismatch, preflight unhandled, invalid wildcard).Access-Control-Allow-* headers.* with specific origins if credentials required.Vary: Origin.curl -v -X OPTIONS command to verify headers.| Case | Strategy |
|---|---|
| No Config | Identify header from error; provide standard middleware snippet. |
| Same-Origin mismatch | Check for port, protocol, or subdomain discrepancies. |
| Reverse Proxy | Ensure proxy doesn't strip headers; add passthrough config. |
flowchart TD
A([Start: CORS Error Resolution]) --> B[Parse inputs]
B --> C{Config available?}
C -- No --> D[Identify missing header
Provide standard config]
C -- Yes --> E[Classify Violation]
E --> F{Request type?}
F -- Simple --> G[No preflight]
F -- Preflight --> H[Needs OPTIONS handler]
F -- Credentialed --> I[Requires specific origin]
G & H & I --> J{Violation?}
J -- Missing Allow-Origin --> K[Set Allow-Origin]
J -- Missing Allow-Methods --> L[Set Allow-Methods]
J -- Missing Allow-Headers --> M[Set Allow-Headers]
J -- Wildcard+credentials --> N[Replace * with specific origin]
J -- Preflight unhandled --> O[Add OPTIONS route 204]
K & L & M & N & O --> P[Write complete config]
P --> Q[Security check:
Validate Origin
Set Vary: Origin]
Q --> R{Behind proxy?}
R -- Yes --> S[Check proxy strips headers
Add passthrough]
R -- No --> T
S --> T[Provide curl test]
T --> U([Output: 5 Sections + Config + Test])
*).@upstash/context7-mcp: Library documentation and examples.| Version | Date | Description |
|---|---|---|
| 1.1.0 | 2026-03-20 | Restructured: moved examples, references, added compatibility/license |
| 1.0.0 | 2026-03-20 | Initial release |
Use to implement a REST or GraphQL API endpoint from a specification or description, including request validation, error handling, and accompanying tests. Activate for building a new API route, resolver, or handler end-to-end. Do NOT use for API design/contract creation, documentation generation, or frontend API consumption.
Use to implement background job processing with a queue, worker, retry with exponential backoff, dead letter queue, and monitoring. Activate when the request involves offloading work from the request cycle (emails, reports, data processing). Do NOT use for real-time event streaming, webhook handling, or scheduled cron jobs.
Use to scaffold a new project from scratch — generating directory structure, configuration files, entry points, and a README skeleton. Activate when starting a new project, service, or package and needing a production-ready starting point. Do NOT use for adding features to existing projects, generating tests, or CI/CD configuration.
Use to design and implement a caching layer for data that is expensive to compute or fetch. Activate for cache-aside, write-through, or write-behind patterns, TTL strategy, and cache invalidation logic. Do NOT use for database query optimization, CDN configuration, or HTTP response caching headers.
Use to generate a CI/CD pipeline configuration for building, testing, and deploying an application. Activate for GitHub Actions, GitLab CI, CircleCI, or similar pipeline tools for any tech stack. Do NOT use for infrastructure provisioning, Dockerfile creation, or deployment strategy design.
Use to generate production-ready code for a new feature, function, class, or module from a description. Activate for writing new code from scratch with error handling, inline documentation, and a self-review checklist. Do NOT use for refactoring existing code, code review, or test generation.