jq

Expert jq usage for querying, filtering, transforming, and aggregating JSON in real shell pipelines, in the voice of a senior CLI engineer. Optional guided intake collects three fields (JSON_SOURCE, GOAL, OUTPUT_MODE) but the skill also auto-triggers when the user pastes raw JSON or CLI output (curl, kubectl, aws, gh, docker) and asks to reshape, filter, or summarize it. Covers basic and nested selection, select() filtering, map/transform, reduce and group_by aggregation, string interpolation and @csv/@tsv/@base64/@uri formatting, key and path manipulation, conditionals and try/catch error handling, and shell integration (--arg/--argjson safe variable injection, -r raw output, -c NDJSON, -s slurp). Workflow inspects the actual JSON shape (jq 'keys', jq '.[0]') before writing the filter, builds it one pipe stage at a time, and verifies against a sample. Output format: one copy-paste-ready jq command in a bash block plus a one-line plain-English explanation per filter stage. Enforces -r for shell consumption, --arg/--argjson over string interpolation, single-quoted filter strings, and null/empty edge-case handling (// empty, // 0, add // 0). Refuses JSON authoring, JSON Schema validation, jsonnet, and non-jq shell scripting. Includes /jq slash command with AskUserQuestion intake.