Path-Specific Instructions Generator

Overview

This skill generates scoped .github/instructions/*.md files that load Just-In-Time (JIT) when specific files are opened. It autonomously analyzes your repository to discover file patterns, extract scope-specific rules from existing code and documentation, and generate precise glob patterns for targeted instruction loading.

Key advantages over global instructions:

• Context Economics: Load rules only when needed (vs always-on global instructions)
• Higher Priority: Path instructions override global instructions
• Precision: Target specific frameworks, file types, or directories

Key principle: Leverage LLM strengths for pattern discovery and rule extraction rather than manual specification.

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Workflow

Step 1: Intent Validation

Confirm the user wants path-specific instructions (not global).

Decision tree:

• User wants scoped/directory/framework-specific rules? → Continue to Step 2
• User wants global repository instructions?
  • → STOP. Redirect them to use generate-repo-instructions skill instead
  • Explain: Global instructions go in .github/copilot-instructions.md
• User wants a custom agent or skill?
  • → STOP. Clarify asset type using Asset Decision Matrix
  • Agent = role-based, Skill = capability-based, Instructions = rules

Proceed only if creating path-specific instructions.

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Step 2: Scope Discovery

Goal: Understand what files/directories to target and what patterns exist.

Load the scope analysis checklist:

cat references/scope_analysis_checklist.md

Work through the checklist to discover:

1. Target identification - What files does the user want to scope?
2. Repository exploration - What file patterns actually exist?
3. Framework detection - What tools/frameworks are in use?
4. Existing conventions - What patterns are already established?

Output: Clear understanding of target scope with concrete file examples.

Critical decision: Be specific or accept ambiguity?

• If user says "test files" but repo has .test.js, .spec.js, AND _test.py
• → Ask: "Target all tests or just JavaScript tests?"
• Don't assume - clarify scope boundaries

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Step 3: Pattern Construction

Goal: Build precise applyTo glob patterns that match intended files only.

Load the pattern construction guide:

cat references/pattern_construction.md

Follow the guide to:

1. Construct candidate patterns based on discovered file structure
2. Test patterns using the glob testing script (optional but recommended)
3. Refine patterns to avoid over-matching or under-matching

Example workflow:

# Test if pattern matches intended files
python3 scripts/test_glob_pattern.py --pattern "tests/**/*.py" --limit 10

# Review matches, refine if needed
python3 scripts/test_glob_pattern.py --pattern "tests/**/*.test.py" --limit 10

Output: Validated glob pattern(s) for applyTo directive.

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Step 4: Rule Extraction

Goal: Discover scope-specific rules (not generic rules that belong in global instructions).

Load the rule discovery checklist:

cat references/rule_discovery_checklist.md

Work through the checklist to extract rules from:

1. Code samples - Read files in target scope, identify patterns
2. Configuration files - Extract settings from linters, formatters, test configs
3. Documentation - Find relevant sections in CONTRIBUTING, style guides
4. Framework conventions - Apply framework best practices

Critical: Context Economics

Load references/context_economics.md to understand the Include/Exclude principle:

✅ Include (Scope-Specific)	❌ Exclude (Too Generic)
"Use pytest fixtures in tests"	"Use 4 spaces for indentation"
"Docs must follow ADR format"	"Write clear commit messages"
"K8s manifests must set limits"	"Follow semantic versioning"

Why? Path instructions have higher priority than global. Use them only for truly scope-specific rules.

Output: List of scope-specific rules with examples from the codebase.

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Step 5: Template Application

Goal: Populate the instruction file with discovered patterns and rules.

Load template examples:

cat references/template_examples.md

Choose the appropriate template based on scope type (testing, docs, config, code).

Populate these fields:

• name: Descriptive kebab-case name
• description: One-sentence scope summary
• applyTo: Validated glob pattern(s) from Step 3
• Scope Introduction - What this applies to
• Standards & Conventions - Framework-specific patterns
• Content Rules - Scope-specific requirements
• Examples - Good examples from actual codebase (not theoretical)

File naming convention:

• .github/instructions/{{scope-type}}-{{content-type}}.md
• Examples: python-testing.md, api-documentation.md, kubernetes-manifests.md
• Use kebab-case, be descriptive (not generic like rules.md)

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Step 6: Validation & Testing

Validate the generated instruction file:

# 1. Validate YAML frontmatter and structure
python3 .github/skills/generate-agent-skills/scripts/validate_skill.py --path .github/instructions/

# 2. Verify glob pattern matches intended files
python3 .github/skills/generate-path-instructions-v2/scripts/test_glob_pattern.py \
  --pattern "tests/**/*.py" \
  --limit 20

# 3. Check rule specificity
# - Are all rules scope-specific?
# - Do rules include examples from actual codebase?
# - Is there any overlap with global instructions?

Final checklist:

• YAML frontmatter is valid (name, description, applyTo)
• Glob patterns tested and match intended files only
• All rules are scope-specific (not generic)
• Examples are from actual codebase (not theoretical)
• Filename is descriptive and uses kebab-case
• No hardcoded secrets or sensitive data

Output to user:

✅ Created: .github/instructions/{{filename}}.md
📌 Applies to: {{glob_pattern}}
📝 Summary: {{one_sentence_description}}

🧪 Tested pattern - matches {{N}} files in repo

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Step 7: Iteration (Optional)

If the user wants to refine:

1. Test in practice - Open a file that should match, verify instruction loads
2. Refine glob pattern - Adjust if over/under-matching
3. Add missing rules - Include additional scope-specific conventions
4. Improve examples - Replace theoretical examples with real code

Common refinements:

• Pattern too broad → Add path prefix (e.g., **/*.test.js → tests/**/*.test.js)
• Rules too generic → Move to global instructions, keep only scope-specific
• Missing context → Add framework-specific best practices

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Resources

scripts/test_glob_pattern.py

Tests glob patterns against actual repository files.

• Input: Glob pattern(s)
• Output: List of matching files
• Purpose: Validate patterns before finalizing instruction file

references/scope_analysis_checklist.md

Guides LLM through repository exploration to discover target scope.

references/pattern_construction.md

Glob syntax reference with common patterns and anti-patterns.

references/rule_discovery_checklist.md

Guides LLM through extracting scope-specific rules from code and docs.

references/template_examples.md

Domain-specific instruction templates (testing, docs, config, code).

references/context_economics.md

Explains when to use path-specific vs global instructions.