Foundry-OSS

General development best practices and common gotchas when working on Biome. Use for avoiding common mistakes, understanding Biome-specific patterns (AST, syntax nodes, string extraction, embedded languages), and learning technical tips.

Guide for creating and writing proper changesets for Biome PRs. Use when a PR introduces user-visible changes (bug fixes, new features, rule changes, formatter changes, parser changes) that need a changeset entry for the CHANGELOG. Trigger when creating changesets, writing changeset descriptions, or choosing the correct change type.

Building AI agents with the Convex Agent component including thread management, tool integration, streaming responses, RAG patterns, and workflow orchestration

Guidelines for building production-ready Convex apps covering function organization, query patterns, validation, TypeScript usage, error handling, and the Zen of Convex design philosophy

How to create, structure, and publish self-contained Convex components with proper isolation, exports, and dependency management

Scheduled function patterns for background tasks including interval scheduling, cron expressions, job monitoring, retry strategies, and best practices for long-running tasks

Complete file handling including upload flows, serving files via URL, storing generated files from actions, deletion, and accessing file metadata from system tables

Writing queries, mutations, actions, and HTTP actions with proper argument validation, error handling, internal functions, and runtime considerations

External API integration and webhook handling including HTTP endpoint routing, request/response handling, authentication, CORS configuration, and webhook signature validation

Schema migration strategies for evolving applications including adding new fields, backfilling data, removing deprecated fields, index migrations, and zero-downtime migration patterns

Patterns for building reactive apps including subscription management, optimistic updates, cache behavior, and paginated queries with cursor-based loading

Defining and validating database schemas with proper typing, index configuration, optional fields, unions, and migration strategies for schema changes

Deep security review patterns for authorization logic, data access boundaries, action isolation, rate limiting, and protecting sensitive operations

Quick security audit checklist covering authentication, function exposure, argument validation, row-level access control, and environment variable handling

Simplify programming long running code flows. Workflows execute durably with configurable retries and delays. Use this skill whenever working with Workflow or related Convex component functionality.

Creates UI components for the Foundry platform using the design system, UntitledUI icons, dark/light mode support, and Storybook stories. Use when building new UI components, adding stories, or when the user invokes /create-ui-component.

Guide for creating high-quality, user-friendly diagnostics in Biome. Use when creating diagnostics for lint rules, adding helpful advice to error messages, implementing code frame displays, or improving diagnostic quality.

Guide for implementing ESLint-to-Biome rule option migrators inside `biome migrate eslint`. Use whenever you add or update a Biome lint rule that has an ESLint source rule with configurable options, need to deserialize plugin-specific ESLint options, or need custom migration logic beyond the auto-generated severity mapping.

Guide for implementing formatting rules using Biome's IR-based formatter infrastructure. Use when implementing formatting for new syntax nodes, handling comments in formatted output, or comparing Biome's formatting against Prettier for JavaScript, CSS, JSON, HTML, or other languages.

Initializes Storybook for the Foundry codebase, discovers all components and pages, then deploys parallel subagents to generate comprehensive stories with visual, interaction, accessibility, and responsive coverage. Use when setting up Storybook or generating stories for components.

Step-by-step guide for creating and implementing lint rules in Biome's analyzer. Use when implementing rules like noVar, useConst, or any custom lint/assist rule, adding code actions to fix diagnostics, implementing semantic analysis for binding references, or adding configurable options to rules.

Creates new Agent Skills for Codex following best practices and documentation. Use when the user wants to create a new skill, extend Codex's capabilities, or package domain expertise into a reusable skill.

Guide for implementing parsers with error recovery for new languages in Biome. Use when adding parsing support for a new language, implementing error recovery in a parser, or writing grammar definitions in .ungram format for JavaScript, CSS, JSON, HTML, GraphQL, or other languages.

Audit and enforce feature parity between web (apps/web) and desktop (apps/desktop) platforms. Use when adding features, reviewing code placement, checking for drift between platforms, or validating that shared packages are used correctly. Triggers on mentions of "parity", "drift", "platform sync", "shared component", or "web vs desktop".

Compares code formatting and formatting IR between Biome and Prettier to ensure that Biome's formatting is consistent and correct. Use when validating formatter changes, debugging formatting differences, or comparing output for JavaScript, TypeScript, CSS, or other languages.

Generate release notes from git history between tags, commits, or date ranges

Reset and seed the Convex database with AcmeCorp reference data (118 requirements, 8 skills, 7 workstreams) for demo preparation

Setup, configure, and manage the Tauri MCP plugin for AI agent debugging of the Foundry desktop app. Use when adding MCP support, configuring the MCP server, troubleshooting MCP connections, or when the user invokes /tauri-mcp.

Guide for working with Biome's module graph and type inference system. Use when implementing type-aware lint rules, understanding type resolution, working on the module graph infrastructure, or implementing type inference for new features.

Process video files with audio extraction, format conversion (mp4, webm), and Whisper transcription. Use when user mentions video conversion, audio extraction, transcription, mp4, webm, ffmpeg, or whisper transcription.

Run a comprehensive governance audit across the Foundry codebase. Spawns parallel agents for security, design system, and Convex pattern review. Use when you want a full compliance report.

Focused design system compliance check on recent changes or specific files. Use when reviewing UI work for token usage, component classes, typography, and color violations.

Comprehensive review of all staged changes before committing. Routes files to appropriate governance domains and produces a go/no-go recommendation. Use before committing significant changes.

"No Black Boxes" enforcement skill. Audits and fixes AI operations that lack proper UI state coverage — missing loading states, streaming progress, activity logs, error handling, or real-time subscriptions. Use when adding AI features, after editing AI action files, or to audit existing code for transparency gaps.

Setup, configure, and manage the Tauri MCP plugin for AI agent debugging of the Foundry desktop app. Use when adding MCP support, configuring the MCP server, troubleshooting MCP connections, or when the user invokes /tauri-mcp.