saved screenshot dimensions did not match the requested viewpo…

Agent diagnostic brief

Exact symptom

saved screenshot dimensions did not match the requested viewport

Where it has been observed

browser automation; mobile screenshot capture.

Likely distinct causes

A successful screenshot command guaranteed the requested viewport dimensions.
Stale tab or emulation state affected the capture clip.

How to distinguish them

The saved image's decoded dimensions equal the requested viewport or clip before visual sign-off.
Check first artifact dimension inspection against the same bounded execution window.
Check fresh browser state against the same bounded execution window.
Check explicit metrics and clip against the same bounded execution window.
Check replacement dimension inspection against the same bounded execution window.
Blank below-the-fold images in a capture with correct dimensions are a different failure: lazy images not yet loaded (see problem-lazy-images-screenshot-false-positive).

Current approaches

Capture from fresh explicit metrics and inspect decoded image dimensions (solution-browser-screenshot-wrong-viewport, revision 1).

Known obsolete approaches

Do not copy a historical workaround across versions without checking current product behavior.
Do not bypass permissions, security controls, or ownership boundaries merely to suppress the symptom.

Versions and freshness

Observed 2026-08-28; Playwright screenshot guidance rechecked 2026-09-11
Editorial and primary-source review date: 2026-09-11.

What remains unknown

Behavior outside the stated products, versions, and environments remains unknown.
Independent reproduction by a different operator has not been established.

Deeper evidence

Problem

Screenshot command succeeds with the wrong viewport dimensions

Observed symptom

A mobile screenshot request completed but the saved image dimensions did not match the requested viewport, making visual acceptance unreliable.
The historical observation is same-operator evidence and does not establish general prevalence.

Operator goal

Complete capture a mobile viewport without mistaking process success for product acceptance.

Current understanding

A mobile screenshot request completed but the saved image dimensions did not match the requested viewport, making visual acceptance unreliable.
Current primary material was reviewed on 2026-09-11; historical behavior remains bounded to Observed 2026-08-28; Playwright screenshot guidance rechecked 2026-09-11.

Known limitations

The observed result applies to one sanitized same-operator execution and the stated version boundary, not every environment.
Recheck product documentation and preserve the variable changed before generalizing the diagnosis.

Known negative results

Accept the first capture based only on command completion. Result: The resulting image was substantially shorter than requested.
No same-operator execution in this release counts as an independent reproduction.
Treating correct image dimensions as proof of a faithful artifact missed blank lazy-loaded images; add an image load-state check next to the dimension check.

Primary and recurrence sources

MDN img element reference
Primary · Primary documentation · Date not supplied · Reviewed 2026-09-11 · Rights: allowed_to_summarize
Current primary material reviewed for claude-historical-corpus-1: MDN img element reference.
Playwright emulation documentation
Primary · Primary documentation · Date not supplied · Reviewed 2026-09-11 · Rights: allowed_to_summarize
Current primary material reviewed for Historical Corpus 1: Playwright emulation documentation.
Playwright screenshot documentation
Primary · Primary documentation · Date not supplied · Reviewed 2026-09-11 · Rights: allowed_to_summarize
Current primary material reviewed for Historical Corpus 1: Playwright screenshot documentation.

Rights and provenance

Origin

Based on a real operator execution; identifying project details removed.

Rights

State: allowed_to_summarize
Review basis: Owner-authorized factual synthesis of the operator's own Claude-assisted execution, independently written from reviewed current primary sources; no transcript expression is published.

Editorial review date

2026-09-11

Known approaches

solution · Revision 1

Capture from fresh explicit metrics and inspect decoded image dimensions

Production corpus importer · 2026-09-11T10:30:00.000Z
Operator Knowledge for Agents editorial · Historical operator record · Digital source: trainedAlgorithmicMedia · Rights: owned

## Candidate action - Capture from fresh explicit metrics and inspect decoded image dimensions. Start by capturing the exact failed stage, current product version, and a bounded before-state. Apply only the smallest evidence-backed change, then repeat the original operation and verify its output independently. This is a candidate procedure supported by one same-operator execution, not a universal fix. ## Applicability - Use when the observed signature is: saved screenshot dimensions did not match the requested viewport. - Observed scope: browser automation; mobile screenshot capture. - Stop if the first failed stage or product boundary differs. ## Procedure - The saved image's decoded dimensions equal the requested viewport or clip before visual sign-off. - Open a fresh tab, set explicit device metrics, capture with an explicit clip, then inspect the saved image dimensions. Verify: The replacement artifact matched the requested mobile dimensions. - Compare the post-change result with the captured before-state and preserve exact readback evidence. ## Limitations - One same-operator execution does not establish cross-operator support. - The procedure does not establish behavior for unreviewed versions, environments, or concurrent state changes. ## Obsolete approaches - Do not reuse a version-specific command or workaround without current documentation review. - Do not infer product completion from a lower-layer command exit alone. ## Negative results - Accept the first capture based only on command completion. Result: The resulting image was substantially shorter than requested. - No external or same-operator report was promoted to independent reproduction credit. ## Evidence boundary - Grounded in current primary source records src-playwright-screenshots-current, src-playwright-emulation-current. - Historical Grade A observation date: 2026-08-28; identifying details removed. - Only immutable manifest executions count as Knowledge for Agents Attempts or Outcomes. ## What remains unknown - Whether the same approach works outside the stated environment remains unknown. - Independent reproduction and universal applicability are not established.

Applicability

State

partial

Text

Applies only when the failed stage matches saved screenshot dimensions did not match the requested viewport.

Facts

Component: screenshot capture
Operation: capture a mobile viewport
Protocol: Chrome DevTools Protocol

Historical date

2026-08-28

Verification grade

Operator relationship

same_operator

Independent reproduction

false

Provenance disclosure

Based on a real operator execution; identifying project details removed.

Pack

Candidate action: Capture from fresh explicit metrics and inspect decoded image dimensions. Start by capturing the exact failed stage, current product version, and a bounded before-state. Apply only the smallest evidence-backed change, then repeat the original operation and verify its output independently. This is a candidate procedure supported by one same-operator execution, not a universal fix.
Applicability: Use when the observed signature is: saved screenshot dimensions did not match the requested viewport.
Observed scope: browser automation; mobile screenshot capture.
Stop if the first failed stage or product boundary differs.
Steps: The saved image's decoded dimensions equal the requested viewport or clip before visual sign-off.
Open a fresh tab, set explicit device metrics, capture with an explicit clip, then inspect the saved image dimensions. Verify: The replacement artifact matched the requested mobile dimensions.
Compare the post-change result with the captured before-state and preserve exact readback evidence.
Limitations: One same-operator execution does not establish cross-operator support.
The procedure does not establish behavior for unreviewed versions, environments, or concurrent state changes.
Obsolete approaches: Do not reuse a version-specific command or workaround without current documentation review.
Do not infer product completion from a lower-layer command exit alone.
Negative results: Accept the first capture based only on command completion. Result: The resulting image was substantially shorter than requested.
No external or same-operator report was promoted to independent reproduction credit.
Evidence boundary: Grounded in current primary source records src-playwright-screenshots-current, src-playwright-emulation-current.
Historical Grade A observation date: 2026-08-28; identifying details removed.
Only immutable manifest executions count as Knowledge for Agents Attempts or Outcomes.
What remains unknown: Whether the same approach works outside the stated environment remains unknown.
Independent reproduction and universal applicability are not established.

Rights

State: allowed_to_summarize
Review basis: Original diagnostic procedure synthesized from owner-authorized execution facts and linked current primary sources; no private source code, logs, or transcript expression is published.

Source ids

src-playwright-screenshots-current
src-playwright-emulation-current