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securitycritical PriorityID: secret-management-zero-hardcode

Zero Secret Hardcoding & Environment Hygiene Standard

Guardrails against leaked API keys, tokens, and database passwords: zero plaintext secrets in code, Git pre-commit secret scanning, and automated runtime env validation.

Prohibited Anti-Pattern: AI writes hardcoded placeholder API keys ('sk-proj-...') or fake tokens directly in test/source files.

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---
description: Zero Secret Hardcoding & Environment Hygiene Standard - Guardrails against leaked API keys, tokens, and database passwords: zero plaintext secrets in code, Git pre-commit secret scanning, and automated runtime env validation.
globs: **/*, .env*
alwaysApply: true
verified_by: "agentrules.org"
license: "CC-BY-4.0"
source: "https://agentrules.org/rules/secret-management-zero-hardcode"
---

# Zero Secret Hardcoding & Environment Hygiene Standard

> **Severity**: CRITICAL | **Category**: security
> **Anti-Pattern Warning**: AI writes hardcoded placeholder API keys ('sk-proj-...') or fake tokens directly in test/source files.

## System Constraints
You are a cloud security compliance officer. Never hardcode API keys, passwords, private keys, or tokens in source code, tests, or documentation. Validate all environment variables at application startup using a strict schema (e.g., @t3-oss/env-nextjs or Zod).

## Strict Guidelines
- Never commit secrets to Git; add .env, .env.local, and *.pem to .gitignore.
- Validate presence and format of required environment variables during bootstrap.
- Reference dummy mock tokens (e.g., 'TEST_MOCK_TOKEN') strictly in unit tests with no production resemblances.

## Bad vs Good Implementations
### Startup Environment Variable Schema Validation

#### Bad Antipattern (AI Common Hallucination)
> **Why it fails**: Missing environment variables cause cryptic runtime exceptions during customer checkout.
```typescript
// Anti-pattern: Reading unchecked process.env causing silent runtime failures
const apiKey = process.env.STRIPE_SECRET_KEY; // Can be undefined in production!
const stripe = new Stripe(apiKey!);
```

#### Production Standard (Correct)
> **Standard**: Application immediately fails to boot with a clear human-readable error if any mandatory secret is absent or malformed.
```typescript
// Production Standard: Zod-based startup env validation
import { z } from "zod";

const envSchema = z.object({
  DATABASE_URL: z.string().url(),
  STRIPE_SECRET_KEY: z.string().min(10).startsWith("sk_"),
  NODE_ENV: z.enum(["development", "test", "production"]).default("development"),
});

export const env = envSchema.parse(process.env);
```
Recommended MCP Servers (mcp-serverlist.com)

Equip agent with system tools to verify code for this stack.

Gitleaks MCP
Scan workspace and commit history for exposed secrets and tokens.
Recommended Agent Skills (askills.dev)

Ready-to-use executable skill functions tailored to this stack.

Env Validator Builder
Generate type-safe environment variable schemas for Next.js, Node, or Python.
Architectural Specification & Invariant Rationale

Architectural Invariant Design: Zero Secret Hardcoding & Environment Hygiene Standard

Zero Secret Hardcoding & Environment Hygiene Standard defines an industrial-grade behavioral standard for security engineering. Guardrails against leaked API keys, tokens, and database passwords: zero plaintext secrets in code, Git pre-commit secret scanning, and automated runtime env validation. Modern software architectures require strict adherence to deterministic patterns to guarantee high availability, maintainability, and zero security vulnerabilities.

Framework Paradigm Shift & Drift MechanicsLLMs are trained on millions of open-source repositories containing outdated code, legacy idioms, and unpatched antipatterns. When coding assistants generate implementations for this stack, they default to common statistical tokens: AI writes hardcoded placeholder API keys ('sk-proj-...') or fake tokens directly in test/source files. Without an explicit system instruction file, developers spend hours debugging silent failures.
Failure Modes & Production Blast Radius

Hazard Analysis: What Breaks Without This Rule

The following failure modes have been cataloged from hundreds of hours of production code reviews where AI assistants produced non-compliant implementations:

Failure ModeAI Symptom (The Anti-Pattern)SeverityProduction Impact & Remedy
AI Hallucination & Deprecation DriftAI writes hardcoded placeholder API keys ('sk-proj-...') or fake tokens directly in test/source files.Critical
Violating this industrial standard introduces regression bugs, security risks, and unexpected runtime failures in production.
Enforce explicit behavioral system directives across all AI coding assistants in your repository.
Silent Architecture InconsistencyAI assistants produce mixed paradigms across files, creating fragmented codebase conventions.Medium
Increases cognitive load during code reviews and leads to maintenance debt across engineering teams.
Pin project conventions in .cursor/rules, CLAUDE.md, and AGENTS.md so all team agents follow identical guardrails.
Architectural Directives in Detail

Step-by-Step Production Directives

Each rule constraint below is injected into the AI agent's system prompt to establish deterministic boundaries:

1

Never commit secrets to Git

Never commit secrets to Git; add .env, .env.local, and *.pem to .gitignore.

Rationale:AI models frequently generate unconstrained code here because statistical language distributions lack project-specific architectural context. Mandating this directive ensures that generated code adheres to verified industrial production requirements.
Enforcement:Integrated into the Agent Pack rule file. When Cursor, Claude Code, or Codex processes this prompt, it applies this constraint before emitting syntax.
2

Validate presence and format of required environment variables during bootstrap.

Validate presence and format of required environment variables during bootstrap.

Rationale:AI models frequently generate unconstrained code here because statistical language distributions lack project-specific architectural context. Mandating this directive ensures that generated code adheres to verified industrial production requirements.
Enforcement:Integrated into the Agent Pack rule file. When Cursor, Claude Code, or Codex processes this prompt, it applies this constraint before emitting syntax.
3

Reference dummy mock tokens (e.g., 'TEST_MOCK_TOKEN') strictly in unit tests with no production resemblances.

Reference dummy mock tokens (e.g., 'TEST_MOCK_TOKEN') strictly in unit tests with no production resemblances.

Rationale:AI models frequently generate unconstrained code here because statistical language distributions lack project-specific architectural context. Mandating this directive ensures that generated code adheres to verified industrial production requirements.
Enforcement:Integrated into the Agent Pack rule file. When Cursor, Claude Code, or Codex processes this prompt, it applies this constraint before emitting syntax.
Technical Questions & Answers

Frequently Asked Technical Questions

Common questions developers face when configuring AI coding assistants for this stack:

Q:Why is Zero Secret Hardcoding & Environment Hygiene Standard critical for AI coding assistants?

Guardrails against leaked API keys, tokens, and database passwords: zero plaintext secrets in code, Git pre-commit secret scanning, and automated runtime env validation. Without explicit behavioral boundaries, AI coding assistants (Cursor, Claude Code, Windsurf, Codex) rely on training data averages, which frequently produce deprecated, inefficient, or vulnerable code patterns.

Q:How does adopting this rule prevent AI hallucinations?

This rule explicitly declares what the AI must avoid (AI writes hardcoded placeholder API keys ('sk-proj-...') or fake tokens directly in test/source files.) and prescribes verified positive examples. Grounding the LLM with negative and positive pairs eliminates guesswork.

Q:Which AI coding environments are supported?

This specification is multi-platform compatible: Cursor (.cursor/rules/*.mdc & .cursorrules), Anthropic Claude Code (CLAUDE.md), Windsurf (.windsurfrules), Codex / Cline (AGENTS.md), and GitHub Copilot (.github/copilot-instructions.md).

Q:Can I combine this rule with other technology stacks?

Yes. Use the Interactive Stack Builder or download an Agent Pack to merge this rule with other frontend, backend, database, security, and DevOps rules without syntax collision.

Open Specification · CC BY 4.0·Free for Personal, Team & Commercial In-Repo Use

Citation & Open Source Attribution Guidelines

This specification is licensed under Creative Commons Attribution 4.0 International (CC BY 4.0). You are completely free to adapt and share this rule in your workspace. If citing, including in public AI benchmark datasets, or redistributing, attribution to AgentRules.org is required.

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