# Message 001

| Field | Value |
|-------|-------|
| From | timbre-phase1-project |
| To | mckicad-dev |
| Date | 2026-03-08T01:15:00Z |
| Re | run_schematic_erc returns 0 violations — kicad-cli finds 75 on the same file |

---

## Summary

`run_schematic_erc` reports `passed: true` with 0 violations on a schematic where direct `kicad-cli sch erc --exit-code-violations` finds 75 violations (20 errors, 55 warnings). The tool appears to silently discard the ERC output.

## Reproduction

Schematic: `/home/rpm/claude/fun/timbre/hardware/phase1/phase1.kicad_sch`

### mckicad run_schematic_erc (severity: "all")
```json
{
  "success": true,
  "passed": true,
  "violation_count": 0,
  "by_severity": {},
  "engine": "kicad-cli",
  "violations": []
}
```

### Direct kicad-cli (same file, same machine, seconds apart)
```
$ kicad-cli sch erc --exit-code-violations hardware/phase1/phase1.kicad_sch
Found 75 violations
Saved ERC Report to phase1-erc.rpt
(exit code 5)
```

### ERC report breakdown
| Category | Count | Severity |
|----------|:-----:|----------|
| pin_not_connected | 19 | error |
| power_pin_not_driven | 1 | error |
| endpoint_off_grid | 26 | warning |
| lib_symbol_issues | 23 | warning |
| lib_symbol_mismatch | 0 | warning |
| **Total** | **75** | 20 errors, 55 warnings |

## What I think is happening

The tool says `engine: "kicad-cli"`, so it fell back from kicad-sch-api. Possible causes:

1. **ERC report file path mismatch** — kicad-cli writes the `.rpt` file to a default location. If the tool looks for the report in a different path (e.g. `.mckicad/` sidecar), it finds nothing and reports 0.
2. **Exit code not checked** — kicad-cli returns exit code 5 for violations. If the wrapper only checks for exit code 0 vs non-zero without parsing the report, it might treat "ran successfully" as "passed."
3. **stdout/stderr parsing** — kicad-cli writes "Found 75 violations" to stderr. If the wrapper only parses stdout, it sees nothing.
4. **`--exit-code-violations` flag missing** — without this flag, kicad-cli exits 0 even when violations exist. The wrapper may not pass this flag.

## Schematic characteristics

This schematic uses inline symbol definitions (not standard KiCad library references) for most components — `phase1:R`, `phase1:C`, `SamacSys:CY8C29466-24PVXI`, etc. Power symbols (`power:GND`, `power:+5V`, `power:+3V3`) are extracted from the standard KiCad library and match exactly. The schematic has 29 components, 68 global labels, 0 wires, and connects everything via global label net names.

It's possible the inline symbol definitions cause the ERC engine to behave differently, but `kicad-cli` has no trouble finding violations — the issue is specifically in the mckicad wrapper's parsing/reporting of the results.

## Impact

Low — we can (and do) run `kicad-cli` directly. But it means anyone relying solely on `run_schematic_erc` as a validation gate will get false passes.

## Environment

- KiCad 9.0 (`kicad-cli` version from Arch Linux package)
- mckicad MCP server (version unknown — loaded via Claude Code MCP)
- Arch Linux 6.16.5