[PR #3124] docs(skill): flag hidden-window throttling in passive browser observation #5631

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opened 2026-10-31 01:08:07 +00:00 by bsakaguchi · 0 comments
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📋 Pull Request Information

Original PR: https://github.com/morluto/rea/pull/3124
Author: @lumatic2
Created: 10/14/2026
Status: 🔄 Open

Base: main ← Head: docs/skill-hidden-window-throttling


📝 Commits (2)

  • 873ad9e docs(skill): flag hidden-window throttling in passive browser observation
  • 062f010 docs(skill): keep unchanged captures inconclusive until a foreground capture

📊 Changes

3 files changed (+16 additions, -2 deletions)

View changed files

📝 .agents/skills/reverse-engineer-anything/SKILL.md (+1 -1)
📝 .agents/skills/reverse-engineer-anything/references/runtime-observation.md (+14 -0)
📝 src/generatedPackageMetadata.ts (+1 -1)

📄 Description

Summary

Passive browser observation attaches to a browser the user already runs. When that window is minimized or covered, Chromium can mark the page hidden and pause requestAnimationFrame, but inspect_web_page and capture_web_screenshot still succeed and their Evidence does not record page visibility. An agent can then report frozen animation or stale time-driven text as page behavior. This adds a short section to the bundled skill's runtime-observation reference so agents check the window state, or compare two captures, before reporting time-dependent behavior.

Problem and expected behavior

Reproduced on Windows 11 x64 (build 26200), Chrome 154.0.8037.99, REA built from main (f3534749), with a self-made loopback page that writes its requestAnimationFrame count into DOM text every frame:

  • Default Chrome instance, window covered by other windows: a CDP probe reported visibilityState: "hidden" and 0 frames in 1 s. Two rea inspect-web-page --include-accessibility-text runs both showed frames: 0. rea capture-web-screenshot exited 0. Neither Evidence's limitations mention visibility.
  • Control instance launched with --disable-backgrounding-occluded-windows --disable-renderer-backgrounding --disable-background-timer-throttling, same page: visibilityState: "visible", ~165 frames/s, and two consecutive inspect-web-page runs showed frames: 918 then frames: 1284.

Expected: the skill tells the agent that unchanged time-driven content from an existing browser can be an observation limitation.

Change and scope

Documentation only: a new "Hidden or covered browser windows" section in .agents/skills/reverse-engineer-anything/references/runtime-observation.md, the bundled skill version bump (50 → 51 on top of current main), and the matching src/generatedPackageMetadata.ts from npm run metadata:generate (same shape as #2286 / a6c3d3a3).

The section is limited to existing-browser observation. Launch-mode scenarios are excluded because PlaywrightScenarioBrowser.ts launches through Playwright, whose default Chromium switches (playwright-core 1.58.2 lib/server/chromium/chromiumSwitches.js) include the three switches above. Not included: recording page visibility in passive Evidence, which would be a provider change and is better discussed separately.

Contract and boundary impact

  • Semantic owner and earliest changed stage: bundled skill instructions.

  • Contribution scope fit and linked maintainer decision: not applicable (documentation within existing boundaries).

  • CLI and MCP/tool-catalog contract: none.

  • Provider, bridge, target-format, or platform compatibility: none.

  • Evidence, artifact, provenance, or reconstruction contract: none.

  • Target selection, authority, upstream behavior, and cleanup details: not applicable.

  • Generated metadata, package, or installation impact: skill version 51 in src/generatedPackageMetadata.ts; no build outputs committed.

  • Documentation or usability only; no target interaction.

Evidence and regression coverage

  • Tests added or updated: none (instruction text only).
  • Base reproduction or other evidence: executed, as above.
  • User-visible CLI/MCP output: not applicable.
  • Remaining proof gaps: reproduced on Windows with Chrome only; macOS/Linux window occlusion and Electron windows were not tested, so the text says "can" rather than "will".

Validation performed

Run on Windows 11 x64 with Node 24.14.1 (the repository pins 24.18.0 in .nvmrc).

  • npm run metadata:generate, then npm run metadata:check — passed.
  • npx oxfmt --check .agents/skills/reverse-engineer-anything — passed.
  • npm run docs:check — passed (5 tests).
  • npm run build, then npm run test:focused -- tests/boundary/filesystem/generatedSkill.test.ts tests/boundary/filesystem/setupSkill.test.ts tests/boundary/filesystem/productCatalog.test.ts tests/acceptance/setup/selectedSkillSetup.test.ts src/domain/completionLedgerGeneration.test.ts — 39 passed, 1 skipped, 1 failed. The failure (productCatalog.test.ts › "keeps translated readmes linked to canonical setup and tool details", missing https://rea.tools/zh-CN/guides/native/ in the zh-CN README) also fails on unmodified main and is unrelated.
  • Recheck on 2026-10-20: merged the head onto current main (aacf740a) with no conflicts, then on Node 24.18.0 ran the tasks behind npm run check (typecheck, lint:built with 0 errors, format:check, knip, metadata:check, verify:architecture-guards) and npm run docs:check (docs:check:built, including the completion-ledger check, and readmeConsistency.test.ts, 5 passed). All passed. The tasks were invoked directly because the run-exclusive wrapper needs the Windows native addon that source checkouts lack (Windows source checkouts).

Compatibility, safety, and release

  • Breaking changes or migration steps: none.
  • Real Hopper/Ghidra, browser, or OS coverage: Chrome 154 on Windows 11 x64, as above.
  • Package or release metadata impact: bundled skill version 51.
  • Security, privacy, process, or containment review: none; no behavior change.

Author readiness

Human owner: @lumatic2

  • I reviewed the final diff and relevant existing code, understand the change and its edge cases, and take responsibility for the complete PR, including AI-assisted work.
  • I checked the evidence above, confirmed it supports the current change, and recorded meaningful validation gaps.
  • I declare this PR ready for initial maintainer review.

Before merge

  • This PR addresses a concrete problem or an agreed enhancement.
  • Material scope and authority questions are resolved, and any required maintainer scope decision covers the final diff.
  • The PR has one focused outcome and the title follows type(scope): outcome.
  • Related issue is linked, or the reason for not linking one is stated above. (No issue: documentation-only fix with the reproduction above.)
  • Tests cover changed observable behavior and meaningful failure paths. (No observable behavior change.)
  • Owning docs, contracts, and generated metadata are updated where needed.
  • User-visible CLI/MCP changes include representative output. (None.)
  • I checked the final diff for secrets, unrelated cleanup, and unsupported claims.

🔄 This issue represents a GitHub Pull Request. It cannot be merged through Gitea due to API limitations.

## 📋 Pull Request Information **Original PR:** https://github.com/morluto/rea/pull/3124 **Author:** [@lumatic2](https://github.com/lumatic2) **Created:** 10/14/2026 **Status:** 🔄 Open **Base:** `main` ← **Head:** `docs/skill-hidden-window-throttling` --- ### 📝 Commits (2) - [`873ad9e`](https://github.com/morluto/rea/commit/873ad9e01722bedad03a6b7a104797ae27f09a9e) docs(skill): flag hidden-window throttling in passive browser observation - [`062f010`](https://github.com/morluto/rea/commit/062f0106828d49179f1f3add1f1a2eceb4830d9d) docs(skill): keep unchanged captures inconclusive until a foreground capture ### 📊 Changes **3 files changed** (+16 additions, -2 deletions) <details> <summary>View changed files</summary> 📝 `.agents/skills/reverse-engineer-anything/SKILL.md` (+1 -1) 📝 `.agents/skills/reverse-engineer-anything/references/runtime-observation.md` (+14 -0) 📝 `src/generatedPackageMetadata.ts` (+1 -1) </details> ### 📄 Description ## Summary Passive browser observation attaches to a browser the user already runs. When that window is minimized or covered, Chromium can mark the page hidden and pause `requestAnimationFrame`, but `inspect_web_page` and `capture_web_screenshot` still succeed and their Evidence does not record page visibility. An agent can then report frozen animation or stale time-driven text as page behavior. This adds a short section to the bundled skill's runtime-observation reference so agents check the window state, or compare two captures, before reporting time-dependent behavior. ## Problem and expected behavior Reproduced on Windows 11 x64 (build 26200), Chrome 154.0.8037.99, REA built from `main` (f3534749), with a self-made loopback page that writes its `requestAnimationFrame` count into DOM text every frame: - Default Chrome instance, window covered by other windows: a CDP probe reported `visibilityState: "hidden"` and 0 frames in 1 s. Two `rea inspect-web-page --include-accessibility-text` runs both showed `frames: 0`. `rea capture-web-screenshot` exited 0. Neither Evidence's limitations mention visibility. - Control instance launched with `--disable-backgrounding-occluded-windows --disable-renderer-backgrounding --disable-background-timer-throttling`, same page: `visibilityState: "visible"`, ~165 frames/s, and two consecutive `inspect-web-page` runs showed `frames: 918` then `frames: 1284`. Expected: the skill tells the agent that unchanged time-driven content from an existing browser can be an observation limitation. ## Change and scope Documentation only: a new "Hidden or covered browser windows" section in `.agents/skills/reverse-engineer-anything/references/runtime-observation.md`, the bundled skill version bump (50 → 51 on top of current `main`), and the matching `src/generatedPackageMetadata.ts` from `npm run metadata:generate` (same shape as #2286 / a6c3d3a3). The section is limited to existing-browser observation. Launch-mode scenarios are excluded because `PlaywrightScenarioBrowser.ts` launches through Playwright, whose default Chromium switches (`playwright-core` 1.58.2 `lib/server/chromium/chromiumSwitches.js`) include the three switches above. Not included: recording page visibility in passive Evidence, which would be a provider change and is better discussed separately. ## Contract and boundary impact - Semantic owner and earliest changed stage: bundled skill instructions. - Contribution scope fit and linked maintainer decision: not applicable (documentation within existing boundaries). - CLI and MCP/tool-catalog contract: none. - Provider, bridge, target-format, or platform compatibility: none. - Evidence, artifact, provenance, or reconstruction contract: none. - Target selection, authority, upstream behavior, and cleanup details: not applicable. - Generated metadata, package, or installation impact: skill version 51 in `src/generatedPackageMetadata.ts`; no build outputs committed. - [x] Documentation or usability only; no target interaction. ## Evidence and regression coverage - Tests added or updated: none (instruction text only). - Base reproduction or other evidence: executed, as above. - User-visible CLI/MCP output: not applicable. - Remaining proof gaps: reproduced on Windows with Chrome only; macOS/Linux window occlusion and Electron windows were not tested, so the text says "can" rather than "will". ## Validation performed Run on Windows 11 x64 with Node 24.14.1 (the repository pins 24.18.0 in `.nvmrc`). - `npm run metadata:generate`, then `npm run metadata:check` — passed. - `npx oxfmt --check .agents/skills/reverse-engineer-anything` — passed. - `npm run docs:check` — passed (5 tests). - `npm run build`, then `npm run test:focused -- tests/boundary/filesystem/generatedSkill.test.ts tests/boundary/filesystem/setupSkill.test.ts tests/boundary/filesystem/productCatalog.test.ts tests/acceptance/setup/selectedSkillSetup.test.ts src/domain/completionLedgerGeneration.test.ts` — 39 passed, 1 skipped, 1 failed. The failure (`productCatalog.test.ts` › "keeps translated readmes linked to canonical setup and tool details", missing `https://rea.tools/zh-CN/guides/native/` in the zh-CN README) also fails on unmodified `main` and is unrelated. - Recheck on 2026-10-20: merged the head onto current `main` (aacf740a) with no conflicts, then on Node 24.18.0 ran the tasks behind `npm run check` (`typecheck`, `lint:built` with 0 errors, `format:check`, `knip`, `metadata:check`, `verify:architecture-guards`) and `npm run docs:check` (`docs:check:built`, including the completion-ledger check, and `readmeConsistency.test.ts`, 5 passed). All passed. The tasks were invoked directly because the `run-exclusive` wrapper needs the Windows native addon that source checkouts lack ([Windows source checkouts](https://github.com/morluto/rea/blob/main/CONTRIBUTING.md#windows-source-checkouts)). ## Compatibility, safety, and release - Breaking changes or migration steps: none. - Real Hopper/Ghidra, browser, or OS coverage: Chrome 154 on Windows 11 x64, as above. - Package or release metadata impact: bundled skill version 51. - Security, privacy, process, or containment review: none; no behavior change. ## Author readiness Human owner: @lumatic2 - [x] I reviewed the final diff and relevant existing code, understand the change and its edge cases, and take responsibility for the complete PR, including AI-assisted work. - [x] I checked the evidence above, confirmed it supports the current change, and recorded meaningful validation gaps. - [x] I declare this PR ready for initial maintainer review. ## Before merge - [x] This PR addresses a concrete problem or an agreed enhancement. - [x] Material scope and authority questions are resolved, and any required maintainer scope decision covers the final diff. - [x] The PR has one focused outcome and the title follows `type(scope): outcome`. - [x] Related issue is linked, or the reason for not linking one is stated above. (No issue: documentation-only fix with the reproduction above.) - [x] Tests cover changed observable behavior and meaningful failure paths. (No observable behavior change.) - [x] Owning docs, contracts, and generated metadata are updated where needed. - [x] User-visible CLI/MCP changes include representative output. (None.) - [x] I checked the final diff for secrets, unrelated cleanup, and unsupported claims. --- <sub>🔄 This issue represents a GitHub Pull Request. It cannot be merged through Gitea due to API limitations.</sub>
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