Ln 651 Query Efficiency Auditor

> **Paths:** File paths (`references/`, `../ln-*`) are relative to this skill directory.

# Query Efficiency Auditor (L3 Worker)

**Type:** L3 Worker

Specialized worker auditing database query patterns for redundancy, inefficiency, and misuse.

## Purpose & Scope

- Audit **query efficiency** (Priority: HIGH)
- Check redundant fetches, batch operation misuse, caching scope problems
- Write structured findings to file with severity, location, effort, recommendations
- Calculate compliance score (X/10) for Query Efficiency category

## Inputs

**MANDATORY READ:** Load `references/audit_worker_core_contract.md`.
Tool policy: follow host AGENTS.md MCP preferences; load `references/mcp_tool_preferences.md` and `references/mcp_integration_patterns.md` only when host policy is absent or MCP behavior is unclear.

Receives `contextStore` with: `tech_stack`, `best_practices`, `db_config` (database type, ORM settings), `codebase_root`, `output_dir`.

**Domain-aware:** Supports `domain_mode` + `current_domain`.

Use `hex-graph` first when reference chains or call paths materially improve query analysis. Use `hex-line` first for local code/config reads when available. If MCP is unavailable, unsupported, or not indexed, continue with built-in `Read/Grep/Glob/Bash` and state the fallback in the report.

## Workflow

Detection policy: use two-layer detection (candidate scan, then context verification); load `references/two_layer_detection.md` only when the verification method is ambiguous.

1) **Parse context from contextStore**
   - Extract tech_stack, best_practices, db_config, output_dir
   - Determine scan_path (same logic as ln-624)

2) **Scan codebase for violations**
   - All Grep/Glob patterns use `scan_path`
   - Trace call chains for redundant fetches (requires reading caller + callee)

3) **Collect findings with severity, location, effort, recommendation**

4) **Calculate score using penalty algorithm**

5) **Write Report:** Build full markdown report in memory per `references/templates/audit_worker_report_template.md`, write to `{output_dir}/ln-651--global.md` in single Write call

6) **Return Summary:** Return minimal summary to coordinator (see Output Format)

## Audit Rules (Priority: HIGH)

### 1. Redundant Entity Fetch
**What:** Same entity fetched from DB twice in a call chain