diff --git a/docs/README.instructions.md b/docs/README.instructions.md index 4101f66b..da7b4a7f 100644 --- a/docs/README.instructions.md +++ b/docs/README.instructions.md @@ -52,6 +52,7 @@ Team and project-specific instructions to enhance GitHub Copilot's behavior for | [Convert Spring JPA project to Spring Data Cosmos](../instructions/convert-jpa-to-spring-data-cosmos.instructions.md)
[![Install in VS Code](https://img.shields.io/badge/VS_Code-Install-0098FF?style=flat-square&logo=visualstudiocode&logoColor=white)](https://aka.ms/awesome-copilot/install/instructions?url=vscode%3Achat-instructions%2Finstall%3Furl%3Dhttps%3A%2F%2Fraw.githubusercontent.com%2Fgithub%2Fawesome-copilot%2Fmain%2Finstructions%2Fconvert-jpa-to-spring-data-cosmos.instructions.md)
[![Install in VS Code Insiders](https://img.shields.io/badge/VS_Code_Insiders-Install-24bfa5?style=flat-square&logo=visualstudiocode&logoColor=white)](https://aka.ms/awesome-copilot/install/instructions?url=vscode-insiders%3Achat-instructions%2Finstall%3Furl%3Dhttps%3A%2F%2Fraw.githubusercontent.com%2Fgithub%2Fawesome-copilot%2Fmain%2Finstructions%2Fconvert-jpa-to-spring-data-cosmos.instructions.md) | Step-by-step guide for converting Spring Boot JPA applications to use Azure Cosmos DB with Spring Data Cosmos | | [Copilot Process tracking Instructions](../instructions/copilot-thought-logging.instructions.md)
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[![Install in VS Code Insiders](https://img.shields.io/badge/VS_Code_Insiders-Install-24bfa5?style=flat-square&logo=visualstudiocode&logoColor=white)](https://aka.ms/awesome-copilot/install/instructions?url=vscode-insiders%3Achat-instructions%2Finstall%3Furl%3Dhttps%3A%2F%2Fraw.githubusercontent.com%2Fgithub%2Fawesome-copilot%2Fmain%2Finstructions%2Fcopilot-thought-logging.instructions.md) | See process Copilot is following where you can edit this to reshape the interaction or save when follow up may be needed | | [Copilot Prompt Files Guidelines](../instructions/prompt.instructions.md)
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[![Install in VS Code Insiders](https://img.shields.io/badge/VS_Code_Insiders-Install-24bfa5?style=flat-square&logo=visualstudiocode&logoColor=white)](https://aka.ms/awesome-copilot/install/instructions?url=vscode-insiders%3Achat-instructions%2Finstall%3Furl%3Dhttps%3A%2F%2Fraw.githubusercontent.com%2Fgithub%2Fawesome-copilot%2Fmain%2Finstructions%2Fprompt.instructions.md) | Guidelines for creating high-quality prompt files for GitHub Copilot | +| [Custom Agent File Guidelines](../instructions/agents.instructions.md)
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[![Install in VS Code Insiders](https://img.shields.io/badge/VS_Code_Insiders-Install-24bfa5?style=flat-square&logo=visualstudiocode&logoColor=white)](https://aka.ms/awesome-copilot/install/instructions?url=vscode-insiders%3Achat-instructions%2Finstall%3Furl%3Dhttps%3A%2F%2Fraw.githubusercontent.com%2Fgithub%2Fawesome-copilot%2Fmain%2Finstructions%2Fagents.instructions.md) | Guidelines for creating custom agent files for GitHub Copilot | | [Custom Instructions File Guidelines](../instructions/instructions.instructions.md)
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[![Install in VS Code Insiders](https://img.shields.io/badge/VS_Code_Insiders-Install-24bfa5?style=flat-square&logo=visualstudiocode&logoColor=white)](https://aka.ms/awesome-copilot/install/instructions?url=vscode-insiders%3Achat-instructions%2Finstall%3Furl%3Dhttps%3A%2F%2Fraw.githubusercontent.com%2Fgithub%2Fawesome-copilot%2Fmain%2Finstructions%2Finstructions.instructions.md) | Guidelines for creating high-quality custom instruction files for GitHub Copilot | | [Dart and Flutter](../instructions/dart-n-flutter.instructions.md)
[![Install in VS Code](https://img.shields.io/badge/VS_Code-Install-0098FF?style=flat-square&logo=visualstudiocode&logoColor=white)](https://aka.ms/awesome-copilot/install/instructions?url=vscode%3Achat-instructions%2Finstall%3Furl%3Dhttps%3A%2F%2Fraw.githubusercontent.com%2Fgithub%2Fawesome-copilot%2Fmain%2Finstructions%2Fdart-n-flutter.instructions.md)
[![Install in VS Code Insiders](https://img.shields.io/badge/VS_Code_Insiders-Install-24bfa5?style=flat-square&logo=visualstudiocode&logoColor=white)](https://aka.ms/awesome-copilot/install/instructions?url=vscode-insiders%3Achat-instructions%2Finstall%3Furl%3Dhttps%3A%2F%2Fraw.githubusercontent.com%2Fgithub%2Fawesome-copilot%2Fmain%2Finstructions%2Fdart-n-flutter.instructions.md) | Instructions for writing Dart and Flutter code following the official recommendations. | | [Dataverse SDK for Python - Advanced Features Guide](../instructions/dataverse-python-advanced-features.instructions.md)
[![Install in VS Code](https://img.shields.io/badge/VS_Code-Install-0098FF?style=flat-square&logo=visualstudiocode&logoColor=white)](https://aka.ms/awesome-copilot/install/instructions?url=vscode%3Achat-instructions%2Finstall%3Furl%3Dhttps%3A%2F%2Fraw.githubusercontent.com%2Fgithub%2Fawesome-copilot%2Fmain%2Finstructions%2Fdataverse-python-advanced-features.instructions.md)
[![Install in VS Code Insiders](https://img.shields.io/badge/VS_Code_Insiders-Install-24bfa5?style=flat-square&logo=visualstudiocode&logoColor=white)](https://aka.ms/awesome-copilot/install/instructions?url=vscode-insiders%3Achat-instructions%2Finstall%3Furl%3Dhttps%3A%2F%2Fraw.githubusercontent.com%2Fgithub%2Fawesome-copilot%2Fmain%2Finstructions%2Fdataverse-python-advanced-features.instructions.md) | Guide specific coding standards and best practices | diff --git a/instructions/agents.instructions.md b/instructions/agents.instructions.md new file mode 100644 index 00000000..8d602c88 --- /dev/null +++ b/instructions/agents.instructions.md @@ -0,0 +1,791 @@ +--- +description: 'Guidelines for creating custom agent files for GitHub Copilot' +applyTo: '**/*.agent.md' +--- + +# Custom Agent File Guidelines + +Instructions for creating effective and maintainable custom agent files that provide specialized expertise for specific development tasks in GitHub Copilot. + +## Project Context + +- Target audience: Developers creating custom agents for GitHub Copilot +- File format: Markdown with YAML frontmatter +- File naming convention: lowercase with hyphens (e.g., `test-specialist.agent.md`) +- Location: `.github/agents/` directory (repository-level) or `agents/` directory (organization/enterprise-level) +- Purpose: Define specialized agents with tailored expertise, tools, and instructions for specific tasks +- Official documentation: https://docs.github.com/en/copilot/how-tos/use-copilot-agents/coding-agent/create-custom-agents + +## Required Frontmatter + +Every agent file must include YAML frontmatter with the following fields: + +```yaml +--- +description: 'Brief description of the agent purpose and capabilities' +name: 'Agent Display Name' +tools: ['read', 'edit', 'search'] +model: 'Claude Sonnet 4.5' +target: 'vscode' +infer: true +--- +``` + +### Core Frontmatter Properties + +#### **description** (REQUIRED) +- Single-quoted string, clearly stating the agent's purpose and domain expertise +- Should be concise (50-150 characters) and actionable +- Example: `'Focuses on test coverage, quality, and testing best practices'` + +#### **name** (OPTIONAL) +- Display name for the agent in the UI +- If omitted, defaults to filename (without `.md` or `.agent.md`) +- Use title case and be descriptive +- Example: `'Testing Specialist'` + +#### **tools** (OPTIONAL) +- List of tool names or aliases the agent can use +- Supports comma-separated string or YAML array format +- If omitted, agent has access to all available tools +- See "Tool Configuration" section below for details + +#### **model** (STRONGLY RECOMMENDED) +- Specifies which AI model the agent should use +- Supported in VS Code, JetBrains IDEs, Eclipse, and Xcode +- Example: `'Claude Sonnet 4.5'`, `'gpt-4'`, `'gpt-4o'` +- Choose based on agent complexity and required capabilities + +#### **target** (OPTIONAL) +- Specifies target environment: `'vscode'` or `'github-copilot'` +- If omitted, agent is available in both environments +- Use when agent has environment-specific features + +#### **infer** (OPTIONAL) +- Boolean controlling whether Copilot can automatically use this agent based on context +- Default: `true` if omitted +- Set to `false` to require manual agent selection + +#### **metadata** (OPTIONAL, GitHub.com only) +- Object with name-value pairs for agent annotation +- Example: `metadata: { category: 'testing', version: '1.0' }` +- Not supported in VS Code + +#### **mcp-servers** (OPTIONAL, Organization/Enterprise only) +- Configure MCP servers available only to this agent +- Only supported for organization/enterprise level agents +- See "MCP Server Configuration" section below + +## Tool Configuration + +### Tool Specification Strategies + +**Enable all tools** (default): +```yaml +# Omit tools property entirely, or use: +tools: ['*'] +``` + +**Enable specific tools**: +```yaml +tools: ['read', 'edit', 'search', 'execute'] +``` + +**Enable MCP server tools**: +```yaml +tools: ['read', 'edit', 'github/*', 'playwright/navigate'] +``` + +**Disable all tools**: +```yaml +tools: [] +``` + +### Standard Tool Aliases + +All aliases are case-insensitive: + +| Alias | Alternative Names | Category | Description | +|-------|------------------|----------|-------------| +| `execute` | shell, Bash, powershell | Shell execution | Execute commands in appropriate shell | +| `read` | Read, NotebookRead, view | File reading | Read file contents | +| `edit` | Edit, MultiEdit, Write, NotebookEdit | File editing | Edit and modify files | +| `search` | Grep, Glob, search | Code search | Search for files or text in files | +| `agent` | custom-agent, Task | Agent invocation | Invoke other custom agents | +| `web` | WebSearch, WebFetch | Web access | Fetch web content and search | +| `todo` | TodoWrite | Task management | Create and manage task lists (VS Code only) | + +### Built-in MCP Server Tools + +**GitHub MCP Server**: +```yaml +tools: ['github/*'] # All GitHub tools +tools: ['github/get_file_contents', 'github/search_repositories'] # Specific tools +``` +- All read-only tools available by default +- Token scoped to source repository + +**Playwright MCP Server**: +```yaml +tools: ['playwright/*'] # All Playwright tools +tools: ['playwright/navigate', 'playwright/screenshot'] # Specific tools +``` +- Configured to access localhost only +- Useful for browser automation and testing + +### Tool Selection Best Practices + +- **Principle of Least Privilege**: Only enable tools necessary for the agent's purpose +- **Security**: Limit `execute` access unless explicitly required +- **Focus**: Fewer tools = clearer agent purpose and better performance +- **Documentation**: Comment why specific tools are required for complex configurations + +## Sub-Agent Invocation (Agent Orchestration) + +Agents can invoke other agents using `runSubagent` to orchestrate multi-step workflows. + +### How It Works + +Include `agent` in tools list to enable sub-agent invocation: + +```yaml +tools: ['read', 'edit', 'search', 'agent'] +``` + +Then invoke other agents with `runSubagent`: + +```javascript +const result = await runSubagent({ + description: 'What this step does', + prompt: `You are the [Specialist] specialist. + +Context: +- Parameter: ${parameterValue} +- Input: ${inputPath} +- Output: ${outputPath} + +Task: +1. Do the specific work +2. Write results to output location +3. Return summary of completion` +}); +``` + +### Basic Pattern + +Structure each sub-agent call with: + +1. **description**: Clear one-line purpose of the sub-agent invocation +2. **prompt**: Detailed instructions with substituted variables + +The prompt should include: +- Who the sub-agent is (specialist role) +- What context it needs (parameters, paths) +- What to do (concrete tasks) +- Where to write output +- What to return (summary) + +### Example: Multi-Step Processing + +```javascript +// Step 1: Process data +const processing = await runSubagent({ + description: 'Transform raw input data', + prompt: `You are the Data Processor specialist. + +Project: ${projectName} +Input: ${basePath}/raw/ +Output: ${basePath}/processed/ + +Task: +1. Read all files from input directory +2. Apply transformations +3. Write processed files to output +4. Create summary: ${basePath}/processed/summary.md + +Return: Number of files processed and any issues found` +}); + +// Step 2: Analyze (depends on Step 1) +const analysis = await runSubagent({ + description: 'Analyze processed data', + prompt: `You are the Data Analyst specialist. + +Project: ${projectName} +Input: ${basePath}/processed/ +Output: ${basePath}/analysis/ + +Task: +1. Read processed files from input +2. Generate analysis report +3. Write to: ${basePath}/analysis/report.md + +Return: Key findings and identified patterns` +}); +``` + +### Key Points + +- **Pass variables in prompts**: Use `${variableName}` for all dynamic values +- **Keep prompts focused**: Clear, specific tasks for each sub-agent +- **Return summaries**: Each sub-agent should report what it accomplished +- **Sequential execution**: Use `await` to maintain order when steps depend on each other +- **Error handling**: Check results before proceeding to dependent steps + +### ⚠️ Tool Availability Requirement + +**Critical**: If a sub-agent requires specific tools (e.g., `edit`, `execute`, `search`), the orchestrator must include those tools in its own `tools` list. Sub-agents cannot access tools that aren't available to their parent orchestrator. + +**Example**: +```yaml +# If your sub-agents need to edit files, execute commands, or search code +tools: ['read', 'edit', 'search', 'execute', 'agent'] +``` + +The orchestrator's tool permissions act as a ceiling for all invoked sub-agents. Plan your tool list carefully to ensure all sub-agents have the tools they need. + +### ⚠️ Important Limitation + +**Sub-agent orchestration is NOT suitable for large-scale data processing.** Avoid using `runSubagent` when: +- Processing hundreds or thousands of files +- Handling large datasets +- Performing bulk transformations on big codebases +- Orchestrating more than 5-10 sequential steps + +Each sub-agent call adds latency and context overhead. For high-volume processing, implement logic directly in a single agent instead. Use orchestration only for coordinating specialized tasks on focused, manageable datasets. + +## Agent Prompt Structure + +The markdown content below the frontmatter defines the agent's behavior, expertise, and instructions. Well-structured prompts typically include: + +1. **Agent Identity and Role**: Who the agent is and its primary role +2. **Core Responsibilities**: What specific tasks the agent performs +3. **Approach and Methodology**: How the agent works to accomplish tasks +4. **Guidelines and Constraints**: What to do/avoid and quality standards +5. **Output Expectations**: Expected output format and quality + +### Prompt Writing Best Practices + +- **Be Specific and Direct**: Use imperative mood ("Analyze", "Generate"); avoid vague terms +- **Define Boundaries**: Clearly state scope limits and constraints +- **Include Context**: Explain domain expertise and reference relevant frameworks +- **Focus on Behavior**: Describe how the agent should think and work +- **Use Structured Format**: Headers, bullets, and lists make prompts scannable + +## Variable Definition and Extraction + +Agents can define dynamic parameters to extract values from user input and use them throughout the agent's behavior and sub-agent communications. This enables flexible, context-aware agents that adapt to user-provided data. + +### When to Use Variables + +**Use variables when**: +- Agent behavior depends on user input +- Need to pass dynamic values to sub-agents +- Want to make agents reusable across different contexts +- Require parameterized workflows +- Need to track or reference user-provided context + +**Examples**: +- Extract project name from user prompt +- Capture certification name for pipeline processing +- Identify file paths or directories +- Extract configuration options +- Parse feature names or module identifiers + +### Variable Declaration Pattern + +Define variables section early in the agent prompt to document expected parameters: + +```markdown +# Agent Name + +## Dynamic Parameters + +- **Parameter Name**: Description and usage +- **Another Parameter**: How it's extracted and used + +## Your Mission + +Process [PARAMETER_NAME] to accomplish [task]. +``` + +### Variable Extraction Methods + +#### 1. **Explicit User Input** +Ask the user to provide the variable if not detected in the prompt: + +```markdown +## Your Mission + +Process the project by analyzing your codebase. + +### Step 1: Identify Project +If no project name is provided, **ASK THE USER** for: +- Project name or identifier +- Base path or directory location +- Configuration type (if applicable) + +Use this information to contextualize all subsequent tasks. +``` + +#### 2. **Implicit Extraction from Prompt** +Automatically extract variables from the user's natural language input: + +```javascript +// Example: Extract certification name from user input +const userInput = "Process My Certification"; + +// Extract key information +const certificationName = extractCertificationName(userInput); +// Result: "My Certification" + +const basePath = `certifications/${certificationName}`; +// Result: "certifications/My Certification" +``` + +#### 3. **Contextual Variable Resolution** +Use file context or workspace information to derive variables: + +```markdown +## Variable Resolution Strategy + +1. **From User Prompt**: First, look for explicit mentions in user input +2. **From File Context**: Check current file name or path +3. **From Workspace**: Use workspace folder or active project +4. **From Settings**: Reference configuration files +5. **Ask User**: If all else fails, request missing information +``` + +### Using Variables in Agent Prompts + +#### Variable Substitution in Instructions + +Use template variables in agent prompts to make them dynamic: + +```markdown +# Agent Name + +## Dynamic Parameters +- **Project Name**: ${projectName} +- **Base Path**: ${basePath} +- **Output Directory**: ${outputDir} + +## Your Mission + +Process the **${projectName}** project located at `${basePath}`. + +## Process Steps + +1. Read input from: `${basePath}/input/` +2. Process files according to project configuration +3. Write results to: `${outputDir}/` +4. Generate summary report + +## Quality Standards + +- Maintain project-specific coding standards for **${projectName}** +- Follow directory structure: `${basePath}/[structure]` +``` + +#### Passing Variables to Sub-Agents + +When invoking a sub-agent, pass all context through template variables in the prompt: + +```javascript +// Extract and prepare variables +const basePath = `projects/${projectName}`; +const inputPath = `${basePath}/src/`; +const outputPath = `${basePath}/docs/`; + +// Pass to sub-agent with all variables substituted +const result = await runSubagent({ + description: 'Generate project documentation', + prompt: `You are the Documentation specialist. + +Project: ${projectName} +Input: ${inputPath} +Output: ${outputPath} + +Task: +1. Read source files from ${inputPath} +2. Generate comprehensive documentation +3. Write to ${outputPath}/index.md +4. Include code examples and usage guides + +Return: Summary of documentation generated (file count, word count)` +}); +``` + +The sub-agent receives all necessary context embedded in the prompt. Variables are resolved before sending the prompt, so the sub-agent works with concrete paths and values, not variable placeholders. + +### Real-World Example: Code Review Orchestrator + +Example of a simple orchestrator that validates code through multiple specialized agents: + +```javascript +async function reviewCodePipeline(repositoryName, prNumber) { + const basePath = `projects/${repositoryName}/pr-${prNumber}`; + + // Step 1: Security Review + const security = await runSubagent({ + description: 'Scan for security vulnerabilities', + prompt: `You are the Security Reviewer specialist. + +Repository: ${repositoryName} +PR: ${prNumber} +Code: ${basePath}/changes/ + +Task: +1. Scan code for OWASP Top 10 vulnerabilities +2. Check for injection attacks, auth flaws +3. Write findings to ${basePath}/security-review.md + +Return: List of critical, high, and medium issues found` + }); + + // Step 2: Test Coverage Check + const coverage = await runSubagent({ + description: 'Verify test coverage for changes', + prompt: `You are the Test Coverage specialist. + +Repository: ${repositoryName} +PR: ${prNumber} +Changes: ${basePath}/changes/ + +Task: +1. Analyze code coverage for modified files +2. Identify untested critical paths +3. Write report to ${basePath}/coverage-report.md + +Return: Current coverage percentage and gaps` + }); + + // Step 3: Aggregate Results + const finalReport = await runSubagent({ + description: 'Compile all review findings', + prompt: `You are the Review Aggregator specialist. + +Repository: ${repositoryName} +Reports: ${basePath}/*.md + +Task: +1. Read all review reports from ${basePath}/ +2. Synthesize findings into single report +3. Determine overall verdict (APPROVE/NEEDS_FIXES/BLOCK) +4. Write to ${basePath}/final-review.md + +Return: Final verdict and executive summary` + }); + + return finalReport; +} +``` + +This pattern applies to any orchestration scenario: extract variables, call sub-agents with clear context, await results. + + +### Variable Best Practices + +#### 1. **Clear Documentation** +Always document what variables are expected: + +```markdown +## Required Variables +- **projectName**: The name of the project (string, required) +- **basePath**: Root directory for project files (path, required) + +## Optional Variables +- **mode**: Processing mode - quick/standard/detailed (enum, default: standard) +- **outputFormat**: Output format - markdown/json/html (enum, default: markdown) + +## Derived Variables +- **outputDir**: Automatically set to ${basePath}/output +- **logFile**: Automatically set to ${basePath}/.log.md +``` + +#### 2. **Consistent Naming** +Use consistent variable naming conventions: + +```javascript +// Good: Clear, descriptive naming +const variables = { + projectName, // What project to work on + basePath, // Where project files are located + outputDirectory, // Where to save results + processingMode, // How to process (detail level) + configurationPath // Where config files are +}; + +// Avoid: Ambiguous or inconsistent +const bad_variables = { + name, // Too generic + path, // Unclear which path + mode, // Too short + config // Too vague +}; +``` + +#### 3. **Validation and Constraints** +Document valid values and constraints: + +```markdown +## Variable Constraints + +**projectName**: +- Type: string (alphanumeric, hyphens, underscores allowed) +- Length: 1-100 characters +- Required: yes +- Pattern: `/^[a-zA-Z0-9_-]+$/` + +**processingMode**: +- Type: enum +- Valid values: "quick" (< 5min), "standard" (5-15min), "detailed" (15+ min) +- Default: "standard" +- Required: no +``` + +## MCP Server Configuration (Organization/Enterprise Only) + +MCP servers extend agent capabilities with additional tools. Only supported for organization and enterprise-level agents. + +### Configuration Format + +```yaml +--- +name: my-custom-agent +description: 'Agent with MCP integration' +tools: ['read', 'edit', 'custom-mcp/tool-1'] +mcp-servers: + custom-mcp: + type: 'local' + command: 'some-command' + args: ['--arg1', '--arg2'] + tools: ["*"] + env: + ENV_VAR_NAME: ${{ secrets.API_KEY }} +--- +``` + +### MCP Server Properties + +- **type**: Server type (`'local'` or `'stdio'`) +- **command**: Command to start the MCP server +- **args**: Array of command arguments +- **tools**: Tools to enable from this server (`["*"]` for all) +- **env**: Environment variables (supports secrets) + +### Environment Variables and Secrets + +Secrets must be configured in repository settings under "copilot" environment. + +**Supported syntax**: +```yaml +env: + # Environment variable only + VAR_NAME: COPILOT_MCP_ENV_VAR_VALUE + + # Variable with header + VAR_NAME: $COPILOT_MCP_ENV_VAR_VALUE + VAR_NAME: ${COPILOT_MCP_ENV_VAR_VALUE} + + # GitHub Actions-style (YAML only) + VAR_NAME: ${{ secrets.COPILOT_MCP_ENV_VAR_VALUE }} + VAR_NAME: ${{ var.COPILOT_MCP_ENV_VAR_VALUE }} +``` + +## File Organization and Naming + +### Repository-Level Agents +- Location: `.github/agents/` +- Scope: Available only in the specific repository +- Access: Uses repository-configured MCP servers + +### Organization/Enterprise-Level Agents +- Location: `.github-private/agents/` (then move to `agents/` root) +- Scope: Available across all repositories in org/enterprise +- Access: Can configure dedicated MCP servers + +### Naming Conventions +- Use lowercase with hyphens: `test-specialist.agent.md` +- Name should reflect agent purpose +- Filename becomes default agent name (if `name` not specified) +- Allowed characters: `.`, `-`, `_`, `a-z`, `A-Z`, `0-9` + +## Agent Processing and Behavior + +### Versioning +- Based on Git commit SHAs for the agent file +- Create branches/tags for different agent versions +- Instantiated using latest version for repository/branch +- PR interactions use same agent version for consistency + +### Name Conflicts +Priority (highest to lowest): +1. Repository-level agent +2. Organization-level agent +3. Enterprise-level agent + +Lower-level configurations override higher-level ones with the same name. + +### Tool Processing +- `tools` list filters available tools (built-in and MCP) +- No tools specified = all tools enabled +- Empty list (`[]`) = all tools disabled +- Specific list = only those tools enabled +- Unrecognized tool names are ignored (allows environment-specific tools) + +### MCP Server Processing Order +1. Out-of-the-box MCP servers (e.g., GitHub MCP) +2. Custom agent MCP configuration (org/enterprise only) +3. Repository-level MCP configurations + +Each level can override settings from previous levels. + +## Agent Creation Checklist + +### Frontmatter +- [ ] `description` field present and descriptive (50-150 chars) +- [ ] `description` wrapped in single quotes +- [ ] `name` specified (optional but recommended) +- [ ] `tools` configured appropriately (or intentionally omitted) +- [ ] `model` specified for optimal performance +- [ ] `target` set if environment-specific +- [ ] `infer` set to `false` if manual selection required + +### Prompt Content +- [ ] Clear agent identity and role defined +- [ ] Core responsibilities listed explicitly +- [ ] Approach and methodology explained +- [ ] Guidelines and constraints specified +- [ ] Output expectations documented +- [ ] Examples provided where helpful +- [ ] Instructions are specific and actionable +- [ ] Scope and boundaries clearly defined +- [ ] Total content under 30,000 characters + +### File Structure +- [ ] Filename follows lowercase-with-hyphens convention +- [ ] File placed in correct directory (`.github/agents/` or `agents/`) +- [ ] Filename uses only allowed characters +- [ ] File extension is `.agent.md` + +### Quality Assurance +- [ ] Agent purpose is unique and not duplicative +- [ ] Tools are minimal and necessary +- [ ] Instructions are clear and unambiguous +- [ ] Agent has been tested with representative tasks +- [ ] Documentation references are current +- [ ] Security considerations addressed (if applicable) + +## Common Agent Patterns + +### Testing Specialist +**Purpose**: Focus on test coverage and quality +**Tools**: All tools (for comprehensive test creation) +**Approach**: Analyze, identify gaps, write tests, avoid production code changes + +### Implementation Planner +**Purpose**: Create detailed technical plans and specifications +**Tools**: Limited to `['read', 'search', 'edit']` +**Approach**: Analyze requirements, create documentation, avoid implementation + +### Code Reviewer +**Purpose**: Review code quality and provide feedback +**Tools**: `['read', 'search']` only +**Approach**: Analyze, suggest improvements, no direct modifications + +### Refactoring Specialist +**Purpose**: Improve code structure and maintainability +**Tools**: `['read', 'search', 'edit']` +**Approach**: Analyze patterns, propose refactorings, implement safely + +### Security Auditor +**Purpose**: Identify security issues and vulnerabilities +**Tools**: `['read', 'search', 'web']` +**Approach**: Scan code, check against OWASP, report findings + +## Common Mistakes to Avoid + +### Frontmatter Errors +- ❌ Missing `description` field +- ❌ Description not wrapped in quotes +- ❌ Invalid tool names without checking documentation +- ❌ Incorrect YAML syntax (indentation, quotes) + +### Tool Configuration Issues +- ❌ Granting excessive tool access unnecessarily +- ❌ Missing required tools for agent's purpose +- ❌ Not using tool aliases consistently +- ❌ Forgetting MCP server namespace (`server-name/tool`) + +### Prompt Content Problems +- ❌ Vague, ambiguous instructions +- ❌ Conflicting or contradictory guidelines +- ❌ Lack of clear scope definition +- ❌ Missing output expectations +- ❌ Overly verbose instructions (exceeding character limits) +- ❌ No examples or context for complex tasks + +### Organizational Issues +- ❌ Filename doesn't reflect agent purpose +- ❌ Wrong directory (confusing repo vs org level) +- ❌ Using spaces or special characters in filename +- ❌ Duplicate agent names causing conflicts + +## Testing and Validation + +### Manual Testing +1. Create the agent file with proper frontmatter +2. Reload VS Code or refresh GitHub.com +3. Select the agent from the dropdown in Copilot Chat +4. Test with representative user queries +5. Verify tool access works as expected +6. Confirm output meets expectations + +### Integration Testing +- Test agent with different file types in scope +- Verify MCP server connectivity (if configured) +- Check agent behavior with missing context +- Test error handling and edge cases +- Validate agent switching and handoffs + +### Quality Checks +- Run through agent creation checklist +- Review against common mistakes list +- Compare with example agents in repository +- Get peer review for complex agents +- Document any special configuration needs + +## Additional Resources + +### Official Documentation +- [Creating Custom Agents](https://docs.github.com/en/copilot/how-tos/use-copilot-agents/coding-agent/create-custom-agents) +- [Custom Agents Configuration](https://docs.github.com/en/copilot/reference/custom-agents-configuration) +- [Custom Agents in VS Code](https://code.visualstudio.com/docs/copilot/customization/custom-agents) +- [MCP Integration](https://docs.github.com/en/copilot/how-tos/use-copilot-agents/coding-agent/extend-coding-agent-with-mcp) + +### Community Resources +- [Awesome Copilot Agents Collection](https://github.com/github/awesome-copilot/tree/main/agents) +- [Customization Library Examples](https://docs.github.com/en/copilot/tutorials/customization-library/custom-agents) +- [Your First Custom Agent Tutorial](https://docs.github.com/en/copilot/tutorials/customization-library/custom-agents/your-first-custom-agent) + +### Related Files +- [Prompt Files Guidelines](./prompt.instructions.md) - For creating prompt files +- [Instructions Guidelines](./instructions.instructions.md) - For creating instruction files + +## Version Compatibility Notes + +### GitHub.com (Coding Agent) +- ✅ Fully supports all standard frontmatter properties +- ✅ Repository and org/enterprise level agents +- ✅ MCP server configuration (org/enterprise) +- ❌ Does not support `model`, `argument-hint`, `handoffs` properties + +### VS Code / JetBrains / Eclipse / Xcode +- ✅ Supports `model` property for AI model selection +- ✅ Supports `argument-hint` and `handoffs` properties +- ✅ User profile and workspace-level agents +- ❌ Cannot configure MCP servers at repository level +- ⚠️ Some properties may behave differently + +When creating agents for multiple environments, focus on common properties and test in all target environments. Use `target` property to create environment-specific agents when necessary.