# Feature Demo: F002 — Answer Verification

> **Generated:** 2026-03-27T22:37:50Z
> **Context source:** spec + discovery only (implementation not read)
> **Feature entry:** [FEATURES.json #F002](FEATURES.json)

---

## What This Feature Does

When an agent submits an `ANSWER`, this feature makes the final pass/fail decision robust to common formatting and representation differences. From a user perspective, it reduces false negatives where the agent is semantically correct but uses a different format (for example numeric formatting differences, casing differences, or reordered list values).

The intended experience is clear and predictable scoring: tolerant float matching, order-insensitive list matching, and unambiguous terminal reward outcomes with fewer frustrating “technically wrong but practically right” rejections.

---

## What Is Already Proven

### Verified in This Demo Run

- Happy-path typed verification scenarios pass for integer, float, string, and list dispatch paths.
- Full integration flow through environment `step()` passes for integer/float/string/list and fallback behavior.
- Edge and error behavior is exercised locally: empty predicted input fails, float tolerance boundary checks pass/fail correctly, and integer coercion failure returns zero reward.
- Existing smoke coverage for answer episode termination still passes.

### Previously Verified Evidence

- `specs/FEATURES.json` (`F002.verification_evidence`) records verifier-approved run: `uv run pytest tests/ -v` with **65/65 passed** at `2026-03-27T22:33:12Z`.
- `specs/F002-IMPLEMENTATION_SPEC.md` Section 7 records completed step evidence including full suite pass and integration pass.

---

## What Still Needs User Verification

- Run one manual episode in your target runtime (your exact dataset/runtime environment) and submit a known-correct `ANSWER` with alternate formatting (for example `42.0` vs `42`) to confirm behavior in your end-to-end setup.

---

## Quickstart / Verification Steps

> Run these commands to see the feature in action:

```bash
uv run pytest tests/test_verifier_integration.py -v
uv run pytest tests/test_verifier.py -v -k "test_verify_integer_exact_match or test_verify_float_within_tolerance or test_verify_string_case_insensitive or test_verify_list_order_insensitive"
```

Prerequisite: dependencies installed via `uv sync`.

---

## Live Local Proof

### Validate typed ANSWER handling through environment flow

This runs the integration scenarios that exercise answer verification via the real environment step flow.

```bash
uv run pytest tests/test_verifier_integration.py -v
```

```
============================= test session starts ==============================
platform darwin -- Python 3.12.3, pytest-9.0.2, pluggy-1.6.0 -- /Users/hjerp/Projects/sql-env-F002-answer-verification/.venv/bin/python3
cachedir: .pytest_cache
rootdir: /Users/hjerp/Projects/sql-env-F002-answer-verification
configfile: pyproject.toml
plugins: cov-7.1.0, anyio-4.13.0
collecting ... collected 6 items

tests/test_verifier_integration.py::test_integer_answer_flow PASSED      [ 16%]
tests/test_verifier_integration.py::test_float_answer_flow PASSED        [ 33%]
tests/test_verifier_integration.py::test_string_answer_flow PASSED       [ 50%]
tests/test_verifier_integration.py::test_list_answer_flow PASSED         [ 66%]
tests/test_verifier_integration.py::test_fallback_when_answer_type_missing PASSED [ 83%]
tests/test_verifier_integration.py::test_type_coercion_failure_returns_zero_reward PASSED [100%]

============================== 6 passed in 7.92s ===============================
```

What to notice: the flow covers all core answer types plus fallback and failure behavior in one environment-facing test surface.

### Confirm happy-path matching behavior for core answer types

This run checks representative dispatcher-level happy cases.

```bash
uv run pytest tests/test_verifier.py -v -k "test_verify_integer_exact_match or test_verify_float_within_tolerance or test_verify_string_case_insensitive or test_verify_list_order_insensitive"
```

```
============================= test session starts ==============================
platform darwin -- Python 3.12.3, pytest-9.0.2, pluggy-1.6.0 -- /Users/hjerp/Projects/sql-env-F002-answer-verification/.venv/bin/python3
cachedir: .pytest_cache
rootdir: /Users/hjerp/Projects/sql-env-F002-answer-verification
configfile: pyproject.toml
plugins: cov-7.1.0, anyio-4.13.0
collecting ... collected 34 items / 30 deselected / 4 selected

tests/test_verifier.py::test_verify_integer_exact_match PASSED           [ 25%]
tests/test_verifier.py::test_verify_float_within_tolerance PASSED        [ 50%]
tests/test_verifier.py::test_verify_string_case_insensitive PASSED       [ 75%]
tests/test_verifier.py::test_verify_list_order_insensitive PASSED        [100%]

======================= 4 passed, 30 deselected in 7.87s =======================
```

What to notice: each answer type has at least one direct pass case that aligns to the feature’s success criteria.

---

## Existing Evidence

- Prior full regression evidence (not re-run in this demo): `uv run pytest tests/ -v` => **65 passed** (`specs/FEATURES.json`, F002 verification evidence).

---

## Manual Verification Checklist

1. Start from a clean shell in project root and run `uv sync`.
2. Execute `uv run pytest tests/test_verifier_integration.py -v` and confirm all 6 integration tests pass.
3. Execute the happy-path dispatcher command from Quickstart and confirm 4 selected tests pass.
4. Optionally run `uv run pytest tests/ -v` to confirm no regressions outside F002.

---

## Edge Cases Exercised

### Empty predicted answer is rejected

```bash
uv run pytest tests/test_verifier.py -v -k "test_verify_empty_predicted_returns_false"
```

```
============================= test session starts ==============================
platform darwin -- Python 3.12.3, pytest-9.0.2, pluggy-1.6.0 -- /Users/hjerp/Projects/sql-env-F002-answer-verification/.venv/bin/python3
cachedir: .pytest_cache
rootdir: /Users/hjerp/Projects/sql-env-F002-answer-verification
configfile: pyproject.toml
plugins: cov-7.1.0, anyio-4.13.0
collecting ... collected 34 items / 33 deselected / 1 selected

tests/test_verifier.py::test_verify_empty_predicted_returns_false PASSED [100%]

======================= 1 passed, 33 deselected in 7.83s =======================
```

This matters because blank answers should fail deterministically rather than being ambiguously normalized.

### Float tolerance boundary and non-numeric rejection

```bash
uv run pytest tests/test_verifier.py -v -k "_compare_float"
```

```
============================= test session starts ==============================
platform darwin -- Python 3.12.3, pytest-9.0.2, pluggy-1.6.0 -- /Users/hjerp/Projects/sql-env-F002-answer-verification/.venv/bin/python3
cachedir: .pytest_cache
rootdir: /Users/hjerp/Projects/sql-env-F002-answer-verification
configfile: pyproject.toml
plugins: cov-7.1.0, anyio-4.13.0
collecting ... collected 34 items / 26 deselected / 8 selected

tests/test_verifier.py::test_compare_float_exact_match PASSED            [ 12%]
tests/test_verifier.py::test_compare_float_within_1pct_tolerance PASSED  [ 25%]
tests/test_verifier.py::test_compare_float_outside_1pct_tolerance PASSED [ 37%]
tests/test_verifier.py::test_compare_float_boundary_exactly_1pct PASSED  [ 50%]
tests/test_verifier.py::test_compare_float_just_over_1pct PASSED         [ 62%]
tests/test_verifier.py::test_compare_float_gold_zero_uses_absolute_tolerance PASSED [ 75%]
tests/test_verifier.py::test_compare_float_gold_zero_fails_large_diff PASSED [ 87%]
tests/test_verifier.py::test_compare_float_non_numeric_returns_false PASSED [100%]

======================= 8 passed, 26 deselected in 7.10s =======================
```

This matters because it validates both tolerant matching and strict rejection when values exceed tolerance or are invalid.

### Type coercion failure returns zero reward in integration flow

```bash
uv run pytest tests/test_verifier_integration.py -v -k "type_coercion_failure"
```

```
============================= test session starts ==============================
platform darwin -- Python 3.12.3, pytest-9.0.2, pluggy-1.6.0 -- /Users/hjerp/Projects/sql-env-F002-answer-verification/.venv/bin/python3
cachedir: .pytest_cache
rootdir: /Users/hjerp/Projects/sql-env-F002-answer-verification
configfile: pyproject.toml
plugins: cov-7.1.0, anyio-4.13.0
collecting ... collected 6 items / 5 deselected / 1 selected

tests/test_verifier_integration.py::test_type_coercion_failure_returns_zero_reward PASSED [100%]

======================= 1 passed, 5 deselected in 6.95s ========================
```

This matters because invalid numeric answers fail cleanly without crashing the answer flow.

---

## Test Evidence (Optional)

> Supplementary proof that the feature works correctly across all scenarios.
> The Live Demo section above shows how to use the feature; this section shows it was tested.

| Test Suite | Tests | Status |
|---|---|---|
| `tests/test_verifier_integration.py` | 6 | All passed |
| `tests/test_verifier.py` selected happy-path dispatcher tests | 4 selected | All passed |
| `tests/test_verifier.py` selected float edge/error tests | 8 selected | All passed |
| `tests/test_smoke.py` selected ANSWER compatibility test | 1 selected | All passed |

Representative command:

```bash
uv run pytest tests/test_smoke.py -v -k "answer"
```

```
============================= test session starts ==============================
platform darwin -- Python 3.12.3, pytest-9.0.2, pluggy-1.6.0 -- /Users/hjerp/Projects/sql-env-F002-answer-verification/.venv/bin/python3
cachedir: .pytest_cache
rootdir: /Users/hjerp/Projects/sql-env-F002-answer-verification
configfile: pyproject.toml
plugins: cov-7.1.0, anyio-4.13.0
collecting ... collected 25 items / 24 deselected / 1 selected

tests/test_smoke.py::TestEnvironment::test_answer_ends_episode_without_budget_decrement PASSED [100%]

======================= 1 passed, 24 deselected in 7.49s =======================
```

---

## Feature Links

- Implementation spec: `specs/F002-IMPLEMENTATION_SPEC.md`
- Verification spec: `specs/F002-VERIFICATION_SPEC.md`

---

*Demo generated by `feature-demo` agent. Re-run with `/feature-demo F002` to refresh.*