---
phase: 13-engine-min-score-filter
verified: 2026-02-24T07:00:00Z
status: passed
score: 5/5 must-haves verified
re_verification: false
---

# Phase 13: Engine Min-Score Filter Verification Report

**Phase Goal:** Users can filter `corpus search` results by a minimum relevance score via a parameter built into the search engine
**Verified:** 2026-02-24T07:00:00Z
**Status:** passed
**Re-verification:** No — initial verification

## Goal Achievement

### Observable Truths

| #  | Truth                                                                                    | Status     | Evidence                                                                           |
|----|------------------------------------------------------------------------------------------|------------|------------------------------------------------------------------------------------|
| 1  | `hybrid_search()` accepts `min_score: float = 0.0` parameter without error              | VERIFIED | Signature at engine.py:56; `test_min_score_parameter_accepted` PASSED              |
| 2  | Calling with `min_score=0.0` returns identical results to no min_score argument          | VERIFIED | engine.py:112 guard `if min_score > 0.0` makes 0.0 a true no-op; `test_min_score_zero_is_noop` PASSED |
| 3  | Calling with `min_score=99.0` returns `[]` regardless of query                          | VERIFIED | Filter comprehension at engine.py:113-116 excludes all real RRF scores; `test_min_score_above_max_returns_empty` PASSED |
| 4  | Results returned when `min_score` is above zero all have `_relevance_score >= min_score` | VERIFIED | Inclusive `>=` comparison at engine.py:115; `test_min_score_filters_below_threshold` PASSED |
| 5  | All 281 existing tests remain green after the engine change                              | VERIFIED | Full suite: 285 passed (281 pre-existing + 4 new), 0 failures                      |

**Score:** 5/5 truths verified

### Required Artifacts

| Artifact                              | Expected                                         | Status   | Details                                                                                        |
|---------------------------------------|--------------------------------------------------|----------|------------------------------------------------------------------------------------------------|
| `tests/search/test_engine.py`        | Four new min_score test functions after existing  | VERIFIED | Functions at lines 378, 385, 391, 397; all four marked `FILT-01` in docstrings                |
| `src/corpus_analyzer/search/engine.py` | `min_score: float = 0.0` param + filter comprehension | VERIFIED | Parameter at line 56; filter guard + comprehension at lines 112-116; docstring at lines 64-67 |

### Key Link Verification

| From                                       | To                                  | Via                                                    | Status   | Details                                                                                               |
|--------------------------------------------|-------------------------------------|--------------------------------------------------------|----------|-------------------------------------------------------------------------------------------------------|
| `src/corpus_analyzer/search/engine.py`    | filtered list (post-text-gate)      | list comprehension on `_relevance_score` after text-gate, before sort block | VERIFIED | `if min_score > 0.0:` guard at line 112; comprehension at lines 113-116 operates on `filtered` (post-text-gate, lines 105-109); sort block follows at line 118 |

### Requirements Coverage

| Requirement | Source Plan  | Description                                                                                   | Status    | Evidence                                                                                              |
|-------------|-------------|-----------------------------------------------------------------------------------------------|-----------|-------------------------------------------------------------------------------------------------------|
| FILT-01     | 13-01-PLAN.md | User can filter `corpus search` results below a threshold with `--min-score <float>` (default `0.0`) | SATISFIED | Engine accepts `min_score: float = 0.0`; 4 tests covering all FILT-01 behaviours pass; REQUIREMENTS.md table marks Phase 13 Complete |

### Anti-Patterns Found

No anti-patterns detected. Neither `engine.py` nor `test_engine.py` contains TODO/FIXME/placeholder comments, empty return stubs, or console-log-only implementations.

### Human Verification Required

None — all success criteria are mechanically verifiable via pytest, ruff, and mypy. The filter operates on in-memory data structures; no visual or real-time behaviour is involved.

### Gaps Summary

No gaps. All five must-have truths verified, both artifacts confirmed substantive and wired, the single key link confirmed in correct position (post-text-gate, pre-sort), FILT-01 satisfied, and all tooling (pytest 285/285, ruff clean, mypy clean) exits 0.

---

## Detailed Evidence

### Artifact Level 1 — Existence

- `src/corpus_analyzer/search/engine.py` — exists, 159 lines, substantive implementation
- `tests/search/test_engine.py` — exists, 407 lines including the four new test functions

### Artifact Level 2 — Substantive (not a stub)

`engine.py`:
- Line 56: `min_score: float = 0.0,` in `hybrid_search()` signature
- Lines 64-67: Docstring for `min_score` parameter with RRF score range context
- Lines 111-116: Guard + filter comprehension — real implementation, not a placeholder

`test_engine.py`:
- `test_min_score_zero_is_noop` (line 378): compares two call results for equality
- `test_min_score_above_max_returns_empty` (line 385): asserts `== []`
- `test_min_score_parameter_accepted` (line 391): type-safety proof
- `test_min_score_filters_below_threshold` (line 397): derives max_score and verifies inclusive threshold

### Artifact Level 3 — Wired

- The `min_score` parameter is consumed inside `hybrid_search()` at lines 112-116; no external caller needed for the engine-layer goal
- The filter operates on `filtered` (not raw `results`), consistent with the plan's stated invariant
- All four test functions invoke `search.hybrid_search(...)` with `min_score=` keyword, confirming the wiring from test to implementation

### Test Suite Results

```
285 passed in 3.36s
```

Four new tests: all PASSED
Full regression: 0 failures, 0 errors

### Tooling Results

```
uv run ruff check .   → All checks passed!
uv run mypy src/      → Success: no issues found in 53 source files
```

---

_Verified: 2026-02-24T07:00:00Z_
_Verifier: Claude (gsd-verifier)_
