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querying-yaml

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Use when querying YAML files, filtering or transforming configuration data, or extracting specific fields from large YAML files like docker-compose.yml or GitHub Actions workflows without loading entire files (saves 80-95% context)

QUICK START

How to use this skill

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I want to install this Agent Skill for this project in Codex.

Source SKILL.md: https://github.com/SebastienDegodez/copilot-instructions/blob/HEAD/plugins/minimal-context-tools/skills/querying-yaml/SKILL.md

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Copying this prompt does not install or run the skill. Review third-party files before use. Codex skill guide

yq: YAML Query and Extraction Tool

Always invoke querying-yaml skill to extract YAML fields - do not execute bash commands directly.

Use yq to extract specific fields from YAML files without reading entire file contents, saving 80-95% context usage.

When to Use yq

Use yq when:

  • Need specific field(s) from structured YAML file
  • File is large (>50 lines) and only need subset of data
  • Querying nested structures in YAML
  • Filtering/transforming YAML data
  • Working with docker-compose.yml, GitHub Actions workflows, K8s configs

Just use Read when:

  • File is small (<50 lines)
  • Need to understand overall structure
  • Making edits (need full context anyway)

Tool Selection

JSON files → Use jq

  • Common: package.json, tsconfig.json, lock files, API responses

YAML files → Use yq

  • Common: docker-compose.yml, GitHub Actions, CI/CD configs

Both tools extract exactly what you need in one command - massive context savings.

Default Strategy

Invoke querying-yaml skill for extracting specific fields from YAML files efficiently. Use instead of reading entire files to save 80-95% context.

Common workflow: finding-files skill → querying-yaml skill → other skills (fuzzy-selecting, replacing-text, viewing-files) for extraction and transformation.

Pipeline Combinations

  • querying-yaml | fuzzy-selecting: Interactive selection from YAML data
  • querying-yaml | replacing-text: Transform YAML to other formats
  • querying-yaml | viewing-files: View extracted YAML with syntax highlighting

Skill Combinations

For Discovery Phase

  • finding-files → querying-yaml: Find YAML config files and extract specific fields
  • searching-text → querying-yaml: Find YAML usage patterns and extract values
  • extracting-code-structure → querying-yaml: Understand API structures before extraction

For Analysis Phase

  • querying-yaml → fuzzy-selecting: Interactive selection from structured data
  • querying-yaml → viewing-files: View extracted data with syntax highlighting
  • querying-yaml → analyzing-code: Extract statistics from YAML output

For Refactoring Phase

  • querying-yaml → replacing-text: Transform YAML data to other formats
  • querying-yaml → querying-json: Convert YAML to JSON for different tools
  • querying-yaml → xargs: Use extracted values as command arguments

Multi-Skill Workflows

  • querying-yaml → querying-json → replacing-text → viewing-files: YAML to JSON transformation with preview
  • querying-yaml → fuzzy-selecting → xargs: Interactive selection and execution based on YAML data
  • finding-files → querying-yaml → searching-text: Find config files, extract values, search usage
  • docker-compose workflow: querying-yaml → fuzzy-selecting → nc (extract ports, test connectivity)

Common Integration Examples

# Get service ports and test connectivity
yq '.services.*.ports' docker-compose.yml | sd - '[^0-9]' '' | fzf | xargs -I {} nc -zv localhost {}

# Extract and filter environment variables
yq '.services.*.environment' docker-compose.yml | sd '\s*-\s*' '' | fzf

Note: Choosing Between jq and yq

  • JSON files (package.json, tsconfig.json): Use jq
  • YAML files (docker-compose.yml, GitHub Actions): Use yq

Quick Examples

# Get service ports from docker-compose
yq '.services.*.ports' docker-compose.yml

# Get specific service configuration
yq '.services.web.image' docker-compose.yml

# List all service names
yq '.services | keys[]' docker-compose.yml

Detailed Reference

For comprehensive yq patterns, syntax, and examples, load yq guide when needing:

  • Complex YAML structure navigation
  • Array manipulation and filtering
  • Data transformation patterns
  • Docker Compose and Kubernetes examples
  • Integration with other tools
  • Core patterns (80% of use cases)
  • Real-world workflows (Docker Compose, GitHub Actions, Kubernetes)
  • Advanced patterns and edge case handling
  • Output formats and pipe composition
  • Best practices and integration with other tools