Querying JSON

jq: JSON Data Extraction Tool

Always invoke jq skill to extract JSON fields - do not execute bash commands directly.

Use jq to extract specific fields from JSON files without loading entire file contents into context.

When to Use jq vs Read

Use jq when:

• Need specific field(s) from structured data file
• File is large (>50 lines) and only need subset
• Querying nested structures
• Filtering/transforming data
• Saves 80-95% context vs reading entire file

Just use Read when:

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

Common File Types

JSON files where jq excels:

• package.json, tsconfig.json
• Lock files (package-lock.json, yarn.lock in JSON format)
• API responses
• Configuration files

Default Strategy

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

Common workflow: fd skill → jq skill → other skills (fzf, sd, bat) for extraction and transformation.

Quick Examples

# Get version from package.json
jq -r .version package.json

# Get nested dependency version
jq -r '.dependencies.react' package.json

# List all dependencies
jq -r '.dependencies | keys[]' package.json

Pipeline Combinations

• jq | fzf: Interactive selection from JSON data
• jq | sd: Transform JSON to other formats
• jq | bat: View extracted JSON with syntax highlighting

Skill Combinations

For Discovery Phase

• fd → jq: Find JSON config files and extract specific fields
• ripgrep → jq: Find JSON usage patterns and extract values
• extracting-code-structure → jq: Understand API structures before extraction

For Analysis Phase

• jq → fzf: Interactive selection from structured data
• jq → bat: View extracted data with syntax highlighting
• jq → tokei: Extract statistics from JSON output

For Refactoring Phase

• jq → sd: Transform JSON data to other formats
• jq → yq: Convert JSON to YAML for different tools
• jq → xargs: Use extracted values as command arguments

Multi-Skill Workflows

• jq → yq → sd → bat: JSON to YAML transformation with preview
• jq → fzf → xargs: Interactive selection and execution based on JSON data
• fd → jq → ripgrep: Find config files, extract values, search usage

Common Integration Examples

# Extract and select dependencies
jq -r '.dependencies | keys[]' package.json | fzf --multi | xargs npm info

# Get and filter package versions
jq -r '.devDependencies | to_entries[] | "\(.key)@\(.value)"' package.json | fzf

Note: Choosing Between jq and yq

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

Detailed Reference

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

• Array manipulation and filtering
• Complex nested data extraction
• Data transformation patterns
• Real-world workflow examples
• Error handling and edge cases
• Core patterns (80% of use cases)
• Real-world workflows
• Advanced patterns
• Pipe composition
• Error handling
• Integration with other tools