AgentRules.org
RulesStacksClientsAuditorPrunerSelf-HealRFCsBenchmarkCLICI/CDAuthorsSubmit
This specification is maintained by the AgentRules Working Group. Have enhancements or want to claim maintainership?Submit Specification →
frontendcritical PriorityID: biome-v1-9-config-vcs-suppression-standard

Biome 1.9 Configuration Inheritance, VCS Integration, and Explicit Rule Suppression Guardrails

Enforces strict configuration architecture in Biome 1.9 across monorepos and standalone repositories. Mandates explicit Git VCS integration to prevent parsing build outputs, centralized schema inheritance via `extends`, and fully qualified inline rule suppressions with mandatory justification strings.

Prohibited Anti-Pattern: Ignoring VCS boundary definitions and using legacy or unexplained suppression comments that bypass CI safety guarantees

Export Ready-to-Drop Configuration

Select format below to copy code or download file directly.

---
description: Biome 1.9 Configuration Inheritance, VCS Integration, and Explicit Rule Suppression Guardrails - Enforces strict configuration architecture in Biome 1.9 across monorepos and standalone repositories. Mandates explicit Git VCS integration to prevent parsing build outputs, centralized schema inheritance via `extends`, and fully qualified inline rule suppressions with mandatory justification strings.
globs: biome.json, biome.jsonc, src/**/*.{ts,tsx,js,jsx,json,jsonc}
alwaysApply: true
verified_by: "agentrules.org"
license: "CC-BY-4.0"
source: "https://agentrules.org/rules/biome-v1-9-config-vcs-suppression-standard"
---

# Biome 1.9 Configuration Inheritance, VCS Integration, and Explicit Rule Suppression Guardrails

> **Severity**: CRITICAL | **Category**: frontend
> **Anti-Pattern Warning**: Ignoring VCS boundary definitions and using legacy or unexplained suppression comments that bypass CI safety guarantees

## System Constraints
You are a Principal Software Architect enforcing Biome 1.9 standards. Mandate robust configuration inheritance, native VCS integration, and deterministic rule suppressions with technical justifications.

## Strict Guidelines
- Engineers MUST ALWAYS configure `vcs.enabled: true`, `vcs.clientKind: 'git'`, and `vcs.useIgnoreFile: true` in the root `biome.json` to prevent Biome from processing untracked build artifacts.
- Engineers MUST ALWAYS structure sub-package configurations in monorepos using the `extends: ["../../biome.json"]` property rather than re-declaring entire rule trees.
- Engineers MUST NEVER use legacy ESLint or Prettier suppression comments (e.g., `// eslint-disable-next-line` or `// prettier-ignore`); all suppressions MUST use Biome's native syntax.
- Inline suppressions MUST ALWAYS follow the format `// biome-ignore lint/<group>/<rule>: <explanation>`, providing an explicit, verifiable technical rationale following the colon delimiter.
- Engineers MUST NOT disable rules globally in `biome.json` to resolve localized legacy patterns; localized overrides via `overrides` arrays or documented inline suppressions MUST be used instead.
- Code SHOULD enforce formatting and linting deterministically in CI via `biome ci --no-errors-on-unmatched --reporter=github` to guarantee uniform developer and CI environments.

## Bad vs Good Implementations
### Biome 1.9 Root Configuration vs Legacy Incomplete Config

#### Bad Antipattern (AI Common Hallucination)
> **Why it fails**: Fails to leverage native VCS integration (`vcs.useIgnoreFile`), manually duplicates `.gitignore` rules in `files.ignore`, and globally disables safety rules (`noExplicitAny`) instead of using granular overrides or suppressions.
```json
{
  "$schema": "https://biomejs.dev/schemas/1.9.4/schema.json",
  "files": {
    "ignore": ["dist", "node_modules", ".next"]
  },
  "linter": {
    "rules": {
      "recommended": true,
      "suspicious": {
        "noExplicitAny": "off"
      }
    }
  }
}
```

#### Production Standard (Correct)
> **Standard**: Enables native Git ignore integration to prevent drift between `.gitignore` and Biome, enforces strict recommended rules globally, and sets deterministic baseline formatting.
```json
{
  "$schema": "https://biomejs.dev/schemas/1.9.4/schema.json",
  "vcs": {
    "enabled": true,
    "clientKind": "git",
    "useIgnoreFile": true,
    "defaultBranch": "main"
  },
  "formatter": {
    "enabled": true,
    "indentStyle": "space",
    "indentWidth": 2,
    "lineWidth": 100
  },
  "linter": {
    "enabled": true,
    "rules": {
      "recommended": true
    }
  }
}
```

### Deterministic Rule Suppression Syntax

#### Bad Antipattern (AI Common Hallucination)
> **Why it fails**: Combines defunct ESLint comments that Biome ignores with a bare Biome suppression lacking the mandatory explanation colon and justification description.
```typescript
// eslint-disable-next-line @typescript-eslint/no-explicit-any
export function deserializePayload(input: string): any {
  // biome-ignore lint/suspicious/noExplicitAny
  const raw: any = JSON.parse(input);
  return raw;
}
```

#### Production Standard (Correct)
> **Standard**: Eliminates legacy ESLint comments and implements the required Biome 1.9 syntax (`// biome-ignore <rule>: <reason>`) with an explicit engineering justification.
```typescript
export function deserializePayload(input: string): unknown {
  // biome-ignore lint/suspicious/noExplicitAny: External legacy webhook schema is untyped and validated downstream via Zod
  const raw: any = JSON.parse(input);
  return raw;
}
```
Recommended MCP Servers (mcp-serverlist.com)

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

Model Context Protocol Filesystem Server
Enables the agent to inspect biome.json configuration hierarchy and file boundaries across monorepo packages.
Recommended Agent Skills (askills.dev)

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

Biome CLI Invoker
Runs `biome check --write` and `biome lint` to validate formatting and suppression syntax deterministically.
Architectural Specification & Invariant Rationale

Architectural Invariant Design: Biome 1.9 Configuration Inheritance, VCS Integration, and Explicit Rule Suppression Guardrails

Biome 1.9 Configuration Inheritance, VCS Integration, and Explicit Rule Suppression Guardrails defines an industrial-grade behavioral standard for frontend engineering. Enforces strict configuration architecture in Biome 1.9 across monorepos and standalone repositories. Mandates explicit Git VCS integration to prevent parsing build outputs, centralized schema inheritance via `extends`, and fully qualified inline rule suppressions with mandatory justification strings. 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: Ignoring VCS boundary definitions and using legacy or unexplained suppression comments that bypass CI safety guarantees 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 DriftIgnoring VCS boundary definitions and using legacy or unexplained suppression comments that bypass CI safety guaranteesCritical
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

Engineers MUST ALWAYS configure `vcs.enabled

Engineers MUST ALWAYS configure `vcs.enabled: true`, `vcs.clientKind: 'git'`, and `vcs.useIgnoreFile: true` in the root `biome.json` to prevent Biome from processing untracked build artifacts.

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

Engineers MUST ALWAYS structure sub-package configurations in monorepos using the `extends

Engineers MUST ALWAYS structure sub-package configurations in monorepos using the `extends: ["../../biome.json"]` property rather than re-declaring entire rule trees.

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

Engineers MUST NEVER use legacy ESLint or Prettier suppression comments (e.g., `// eslint-disable-next-line` or `// prettier-ignore`)

Engineers MUST NEVER use legacy ESLint or Prettier suppression comments (e.g., `// eslint-disable-next-line` or `// prettier-ignore`); all suppressions MUST use Biome's native syntax.

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.
4

Inline suppressions MUST ALWAYS follow the format `// biome-ignore lint/<group>/<rule>

Inline suppressions MUST ALWAYS follow the format `// biome-ignore lint/<group>/<rule>: <explanation>`, providing an explicit, verifiable technical rationale following the colon delimiter.

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.
5

Engineers MUST NOT disable rules globally in `biome.json` to resolve localized legacy patterns

Engineers MUST NOT disable rules globally in `biome.json` to resolve localized legacy patterns; localized overrides via `overrides` arrays or documented inline suppressions MUST be used instead.

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.
6

Code SHOULD enforce formatting and linting deterministically in CI via `biome ci --no-errors-on-unmatched --reporter=github` to guarantee uniform developer and CI environments.

Code SHOULD enforce formatting and linting deterministically in CI via `biome ci --no-errors-on-unmatched --reporter=github` to guarantee uniform developer and CI environments.

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 Biome 1.9 Configuration Inheritance, VCS Integration, and Explicit Rule Suppression Guardrails critical for AI coding assistants?

Enforces strict configuration architecture in Biome 1.9 across monorepos and standalone repositories. Mandates explicit Git VCS integration to prevent parsing build outputs, centralized schema inheritance via `extends`, and fully qualified inline rule suppressions with mandatory justification strings. 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 (Ignoring VCS boundary definitions and using legacy or unexplained suppression comments that bypass CI safety guarantees) 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.

Related FRONTEND Rules

View all rules →
frontend
119

SolidStart 1.0 Server Functions & Async Boundaries Production Standard

SolidStart 1.0 relies on the Vinxi bundler to split `server$` closures into independent HTTP POST RPC endpoints. Direct lexical closure over client signals within `server$` scopes or failure to demarcate async boundaries with `<Suspense>` causes silent serialization failures, client-bundle secret leaks, and SSR hydration mismatches. Enforcing strict parameter passing, runtime input validation, and Solid async primitives maintains security and fine-grained reactivity across network boundaries.

frontend
119

Astro 5 Actions & Content Layer Production Standard

Enforces strict type safety and architectural correctness for Astro 5 Server Actions and the zero-waterfall Content Layer API. Prevents runtime contract mismatches, hydration mismatches, and unhandled mutation exceptions across dynamic and prerendered boundaries. Failure to follow these patterns leads to silent data fetching waterfalls, build-time cache corruptions, and unhandled server action exceptions.

frontend
51

Nuxt 4 Nitro Server Engine & Shared Directory Production Standard

Nuxt 4 enforces strict boundary segregation between client UI in the app/ directory, backend endpoints in server/, and universal contracts in shared/. Violating cross-boundary isolation or maintaining module-scoped state in Nitro server handlers causes catastrophic cross-request data corruption and hydration mismatches under concurrent production traffic. Architects must enforce request-isolated H3 event contexts, universal serialization schemas, and strict path-alias boundaries.

1 Rule in Stack

Biome