# Sprint 257 Execution Tracker - 2026-02-26

## Scope
- `sprint257_plan.md`

## Implemented

Pipeline gating enhancement in `tools/mcp/run_sprint_taskitem_pipeline.sh`:
- Added:
  - `WSTONE_NATIVE_RAW_TOP_GAP_REQUIRE_UPLIFT`
- Raw candidate search now hard-fails with exit code `18` when:
  - uplift is required but weighted top-gap mode is not configured (`WSTONE_NATIVE_RAW_TOP_GAP_WEIGHTED_SELECT=1` + valid backlog file), or
  - `best_top_gap_score <= baseline_top_gap_score`
- Raw search summary now emits:
  - `top_gap_require_uplift`

## Validation Artifacts

Gate OFF (expected pass):
- `logs/taskitem_runs/01a_fallback_intake_spec_20260226_162632/00_summary.json`

Gate ON (expected fail):
- `logs/taskitem_runs/01a_fallback_intake_spec_20260226_162633/02ae_raw_candidate_search.json`
- command exit code: `18`

Observed result on hard sample:
- `baseline_top_gap_score=0`
- `best_top_gap_score=0`
- with required uplift enabled, run blocked as designed.

## Explicit Completion Signal

- Sprint 257: `DONE` (implemented + enforced no-uplift guard for top-gap policy)