Full-page screenshots of tall pages routinely exceeded 2000px on the
longest dimension, silently bricking the agent's session: the
resulting base64 reached the Anthropic vision API which rejected the
oversized image, leaving the agent burning turns on a useless blob
with no stderr trace from the browse side.
Adds browse/src/screenshot-size-guard.ts as a shared helper:
- guardScreenshotBuffer(buf) → downscales in-memory if max(w,h) > 2000
- guardScreenshotPath(path) → file-mode variant that rewrites in place
- Aspect ratio preserved via sharp's resize fit:inside
- Stderr diagnostic on any downscale so callers can see when it fired
- Lazy sharp import so non-screenshot paths pay no startup cost
Wires the guard into all three full-page callsites codex review
flagged:
- browse/src/snapshot.ts: annotated + heatmap fullPage captures
- browse/src/meta-commands.ts: screenshot command (path + base64
fullPage modes) plus the responsive 3-viewport sweep
- browse/src/write-commands.ts: prettyscreenshot fullPage path
Covers seven unit cases (pass-through, downscale, aspect ratio,
exactly-2000px edge, file-mode rewrite) plus a static invariant test
that fails the build if any of the three callsites stops importing the
guard.
Closes#1214.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Garry Tan