Two pure stdlib helpers that shrink what lands in the model prompt:
* compress_diff(diff, *, context=2) — re-renders a unified diff so each
hunk keeps only unchanged lines on either side of its +/- lines.
File headers + hunk headers + +/- lines preserved verbatim. Pure-context
hunks dropped (rare but legal — git emits them on whitespace-only diffs).
Collapsed gaps of >=5 lines emit a single '@@ … N context line(s) omitted
… @@' marker so the reviewer knows code was elided. Smaller gaps stay
silent — the marker would be longer than the elision.
* extract_finding_bullets(review_body) — pulls the lines of a prior review
that look like a pragent finding (- **[SEVERITY]** path:line — …) and
drops everything else. The model already has the diff; repeating the
prose is just token burn.
No I/O, no network. Tolerant of malformed input — never raises. 14 unit
tests cover both helpers, including an anchor-preservation check against
parse_diff_anchors to guarantee compress-then-anchor still works.
Wiring in ai_review/opencode_review lives in the next commit.
Marcos
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