# Code review — Step 2: Implement stream slicing and stats

**Verdict: Approved**

The remaining Step 2 fixes from R011 are present. NP/IF rolling windows are now anchored to the requested elapsed segment start for time-selected segments, and distance-selected derived calculations skip non-finite time samples before split-half or rolling-window math. The pure calculator and tool boundary now satisfy the Step 2 contract for narrow canonical stream fetching, inclusive time/distance slicing, deterministic scalar stats, derived-stat minimums, actionable missing/out-of-range errors, and analyzer `_meta.insufficient_sample` alignment.

## Findings

No blocking or medium issues found for Step 2.

## Notes

- `golangci-lint run ./internal/analysis ./internal/tools` still reports the expected Step 3 registration-related unused functions (`newComputeActivitySegmentStatsTool` and `computeActivitySegmentStatsInputSchema`). This should clear when the tool is registered in the next step.

## Verification performed

- `git diff b93bbe1..HEAD --name-only`
- `git diff b93bbe1..HEAD`
- Read `PROMPT.md`, `STATUS.md`, and the changed analysis/tool files.
- `go test ./internal/analysis ./internal/tools` — passed
- `go test ./...` — passed
- `golangci-lint run ./internal/analysis ./internal/tools` — failed only on the expected Step 3 registration-related unused functions noted above.
