VERDICT: PASS

## What was tested

### Stage 1: Compact dump output

**Guard checks (all passed):**
- `cstat dump --path .` produces valid JSON at 2,898 bytes (well under 10KB limit)
- All 6 top-level keys present: `cstat_version`, `project`, `scores`, `diagnostic_counts`, `worst_items`, `suggested_drilldowns`
- `worst_items` contains exactly 5 entries (capped correctly; verified with a synthetic 20-function project that generates 253 alerts — still capped at 5)
- Each `suggested_drilldowns` entry includes both `command` and `reason` fields
- `hotspots` and `topology` sections removed from output
- Full `diagnostics` array replaced with `diagnostic_counts`

**Drilldown logic verified:**
- Categories with alerts > 0 correctly map to their subcommands (complexity, redundancy, deps)
- Categories with 0 alerts (bloated_file, dead_code, too_many_params, high_coupling, cyclic_deps) correctly produce no drilldown entries
- Categories mapping to the same command are correctly merged with combined reasons
- Drilldowns are sorted by total alert count descending

**Boundary inputs:**
- Empty directory (no Cargo.toml): fails gracefully with "No Cargo.toml found" error message
- Nonexistent path: fails gracefully with "Cannot resolve path ... No such file or directory"
- Trivial single-function project: produces valid JSON with empty `worst_items` and empty `suggested_drilldowns`, zero diagnostics
- Malformed Rust source (syntax error): produces valid JSON, does not crash, reports 0 functions

**Subcommand compatibility:**
- All individual `--json` subcommands referenced in drilldown mappings produce valid JSON: `complexity`, `redundancy`, `deps`, `loc`, `datapaths`, `graph`
- `cstat summary` is untouched and renders correctly

### Stage 2: judge.md update

**Guard checks (all passed):**
- `judge.md` contains "## 3. Measure it" section
- References both `cstat dump --path .` and `cstat summary --path .`
- Frames metrics as "evidence, not as automatic pass/fail criteria"

### Code quality

- `dump.rs` (232 lines) is clean, well-structured, and easy to follow
- Clear naming: `DumpOutput`, `DiagnosticCounts`, `build_worst_items`, `build_drilldowns`, `category_name`
- Logical section separators with comments
- No TODOs, FIXMEs, debug prints, or dead code
- Not flagged in its own worst_items analysis

### Metrics (cstat on itself)

- Modularity: 0.92, Complexity: 0.81, Maintainability: 0.78
- All alert-level items are pre-existing large functions (diagnostics, summary, map) — not introduced by this change
- `dump.rs` does not appear in worst items

### Minor note (not blocking)

The `suggested_drilldowns` commands omit `--path .` (e.g., `cstat complexity --json` instead of `cstat complexity --json --path .`). The plan's example JSON includes `--path .`, but the mapping logic section does not. The commands are still usable — consumers just need to add their own `--path`. This is a cosmetic difference, not a functional one.