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+---
+description: 'Guidelines for creating high-quality prompt files for GitHub Copilot'
+applyTo: '**/*.prompt.md'
+---
+
+# Copilot Prompt Files Guidelines
+
+Instructions for creating effective and maintainable prompt files that guide GitHub Copilot in delivering consistent, high-quality outcomes across any repository.
+
+## Scope and Principles
+- Target audience: maintainers and contributors authoring reusable prompts for Copilot Chat.
+- Goals: predictable behaviour, clear expectations, minimal permissions, and portability across repositories.
+- Primary references: VS Code documentation on prompt files and organization-specific conventions.
+
+## Frontmatter Requirements
+- Include `description` (single sentence, actionable outcome), `mode` (explicitly choose `ask`, `edit`, or `agent`), and `tools` (minimal set of tool bundles required to fulfil the prompt).
+- Declare `model` when the prompt depends on a specific capability tier; otherwise inherit the active model.
+- Preserve any additional metadata (`language`, `tags`, `visibility`, etc.) required by your organization.
+- Use consistent quoting (single quotes recommended) and keep one field per line for readability and version control clarity.
+
+## File Naming and Placement
+- Use kebab-case filenames ending with `.prompt.md` and store them under `.github/prompts/` unless your workspace standard specifies another directory.
+- Provide a short filename that communicates the action (for example, `generate-readme.prompt.md` rather than `prompt1.prompt.md`).
+
+## Body Structure
+- Start with an `#` level heading that matches the prompt intent so it surfaces well in Quick Pick search.
+- Organize content with predictable sections. Recommended baseline: `Mission` or `Primary Directive`, `Scope & Preconditions`, `Inputs`, `Workflow` (step-by-step), `Output Expectations`, and `Quality Assurance`.
+- Adjust section names to fit the domain, but retain the logical flow: why → context → inputs → actions → outputs → validation.
+- Reference related prompts or instruction files using relative links to aid discoverability.
+
+## Input and Context Handling
+- Use `${input:variableName[:placeholder]}` for required values and explain when the user must supply them. Provide defaults or alternatives where possible.
+- Call out contextual variables such as `${selection}`, `${file}`, `${workspaceFolder}` only when they are essential, and describe how Copilot should interpret them.
+- Document how to proceed when mandatory context is missing (for example, “Request the file path and stop if it remains undefined”).
+
+## Tool and Permission Guidance
+- Limit `tools` to the smallest set that enables the task. List them in the preferred execution order when the sequence matters.
+- If the prompt inherits tools from a chat mode, mention that relationship and state any critical tool behaviours or side effects.
+- Warn about destructive operations (file creation, edits, terminal commands) and include guard rails or confirmation steps in the workflow.
+
+## Instruction Tone and Style
+- Write in direct, imperative sentences targeted at Copilot (for example, “Analyze”, “Generate”, “Summarize”).
+- Keep sentences short and unambiguous, following Google Developer Documentation translation best practices to support localization.
+- Avoid idioms, humor, or culturally specific references; favour neutral, inclusive language.
+
+## Output Definition
+- Specify the format, structure, and location of expected results (for example, “Create `docs/adr/adr-XXXX.md` using the template below”).
+- Include success criteria and failure triggers so Copilot knows when to halt or retry.
+- Provide validation steps—manual checks, automated commands, or acceptance criteria lists—that reviewers can execute after running the prompt.
+
+## Examples and Reusable Assets
+- Embed Good/Bad examples or scaffolds (Markdown templates, JSON stubs) that the prompt should produce or follow.
+- Maintain reference tables (capabilities, status codes, role descriptions) inline to keep the prompt self-contained. Update these tables when upstream resources change.
+- Link to authoritative documentation instead of duplicating lengthy guidance.
+
+## Quality Assurance Checklist
+- [ ] Frontmatter fields are complete, accurate, and least-privilege.
+- [ ] Inputs include placeholders, default behaviours, and fallbacks.
+- [ ] Workflow covers preparation, execution, and post-processing without gaps.
+- [ ] Output expectations include formatting and storage details.
+- [ ] Validation steps are actionable (commands, diff checks, review prompts).
+- [ ] Security, compliance, and privacy policies referenced by the prompt are current.
+- [ ] Prompt executes successfully in VS Code (`Chat: Run Prompt`) using representative scenarios.
+
+## Maintenance Guidance
+- Version-control prompts alongside the code they affect; update them when dependencies, tooling, or review processes change.
+- Review prompts periodically to ensure tool lists, model requirements, and linked documents remain valid.
+- Coordinate with other repositories: when a prompt proves broadly useful, extract common guidance into instruction files or shared prompt packs.
+
+## Additional Resources
+- [Prompt Files Documentation](https://code.visualstudio.com/docs/copilot/customization/prompt-files#_prompt-file-format)
+- [Awesome Copilot Prompt Files](https://github.com/github/awesome-copilot/tree/main/prompts)
+- [Tool Configuration](https://code.visualstudio.com/docs/copilot/chat/chat-agent-mode#_agent-mode-tools)