Rule overview

eslint-plugin-copilot focuses on repository customization quality for GitHub Copilot.

What the rules cover

required frontmatter metadata for prompt, instructions, custom-agent, chatmode, and skill definition files
non-empty, correctly shaped optional metadata such as prompt and agent name, argument-hint, tools, model, and skill license
repository-relative applyTo glob validation for path-specific instructions
practical repository-instructions guidance such as the code-review 4,000-character budget
baseline repository setup when you opt into prompts, custom agents, chat modes, skills, agent instruction files, or path-specific instructions
duplicate effective names across prompts, custom agents, skills, and shared slash-command namespaces
relative-link and existing-target checks for prompts, instructions, agents, and skills
modern custom-agent-only metadata such as subagent wiring, invocation controls, targets, MCP servers, hooks, and handoffs
GitHub-target-specific custom-agent metadata such as mcp-servers targeting and JSON config references
repository-relative and existing-path validation for agent hook cwd values
repository hook JSON schema quality under .github/hooks/*.json, including version, hooks, event arrays, hook type, shell commands, cwd, timeoutSec, and env
repository hook maintainability checks such as avoiding empty event arrays and oversized timeout budgets
migration pressure away from legacy .chatmode.md customization files toward modern .agent.md agents
modern fully-qualified tools metadata in prompt, custom agent, and legacy chat mode files