# Security Deployment

> Secure and deploy Cloudflare Workers applications with secrets, least-privilege bindings, authz, tenant isolation, input validation, CORS, preview/prod separation, migrations, rollout, and rollback practices. Use before shipping Cloudflare code.

- Skill: `zllovesuki/security-deployment` (Agent Skill)
- Install (CLI): `npx skillmds@latest add zllovesuki/security-deployment`
- Raw SKILL.md: https://api.skillmd.com/api/skills/zllovesuki/security-deployment/raw
- Safety review: pending
- Works with: Claude Code, Claude.ai, OpenAI Codex
- Category: DevOps & Infra
- Author: zllovesuki (https://skillmd.com/u/zllovesuki)
- Updated: 2026-09-22
- Page: https://skillmd.com/skills/zllovesuki/security-deployment

---

# Security and Deployment

Use this skill before shipping a Cloudflare Worker or modifying production bindings.

## Security stance

- Bindings are capabilities. Give each Worker only the bindings it needs.
- Keep secrets out of source control and `wrangler.jsonc`.
- Authenticate at the Worker boundary; authorize inside every data/tool operation.
- Validate all request input, queue messages, workflow parameters, WebSocket messages, and AI tool calls.
- Include tenant ID in every multi-tenant data access path.
- Avoid arbitrary user-controlled outbound fetches unless SSRF risk is explicitly addressed.

## Secrets and config

- Use `vars` only for non-secret values.
- Use `wrangler secret put NAME` or a secret binding for credentials.
- Rotate secrets through deployment runbooks.
- Do not echo secrets into logs, error responses, AI prompts, or queue messages.

## Authz helper pattern

```ts
type Principal = { userId: string; tenantId: string; roles: string[] };

function requireTenant(principal: Principal, tenantId: string) {
  if (principal.tenantId !== tenantId) {
    throw new Response("Forbidden", { status: 403 });
  }
}
```

## CORS rules

- Do not use `*` for credentialed APIs.
- Keep an allowlist of origins per environment.
- Return CORS headers consistently for preflight and actual responses.
- Validate auth even when CORS permits the origin.

## Deployment checklist

- [ ] `wrangler.jsonc` has correct environment-specific bindings.
- [ ] Generated types are up to date.
- [ ] Migrations are tested and ordered.
- [ ] Durable Object migrations are append-only.
- [ ] Secrets are present in target environment.
- [ ] Observability is enabled before rollout.
- [ ] Rollback or traffic-disable plan is written.
- [ ] Production smoke test covers a real binding call.

## Migration/deployment ordering

For schema changes:

1. Expand: deploy additive schema.
2. Deploy code that can read/write old and new shape.
3. Backfill or migrate asynchronously.
4. Switch reads to new shape.
5. Contract: remove old columns/tables only after verification.

## AI/tool security

- Treat model output as untrusted.
- Validate tool arguments generated by the model.
- Enforce authorization in tools, not prompts.
- Do not include secrets or unrelated tenant data in prompts.
- Require confirmation for destructive/expensive actions.

## Anti-patterns

- One Worker has every binding because it is convenient.
- Preview environment points at production D1/R2/KV by accident.
- Authorization enforced only in the frontend.
- Queue consumers trust messages without schema validation.
- Raw internal errors are returned to users.