refactor(emcn): own shared shimmer text treatment by BillLeoutsakosvl346 · Pull Request #8252 · simstudioai/sim

BillLeoutsakosvl346 · 2026-09-24T19:13:14Z

Summary

Move the existing shared shimmer text treatment into EMCN, with the same CSS animation and reduced-motion behavior.
Use it in activity status, agent streaming chrome, and the thinking loader while retaining each caller's typography and layout.
Keep the existing static thinking-loader label unchanged and update the relevant component mocks.

Validation

Focused EMCN and app tests: 44 passed on the refreshed head.
EMCN and app TypeScript checks passed.
Biome and git diff checks passed on changed files.
The local design diff checker reported no introduced confirmed findings or coverage failures against current staging (d8e7e923a2).
Matched source-derived captures in light and dark, at 16px and 20px root size, with ordinary and reduced motion. All eight cases matched before and after computed geometry and shimmer styling. Staging subsequently changed the active label wording in both base and head; the captures remain a comparison of the shimmer treatment. Review artifacts are stored outside this product PR.

vercel · 2026-09-24T19:13:21Z

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Project	Deployment	Actions	Updated
docs	Ready	Preview	Oct 3, 2026 3:25am UTC

BillLeoutsakosvl346 · 2026-09-24T19:13:21Z

@greptile review this PR

BillLeoutsakosvl346 · 2026-09-24T19:13:25Z

@cubic-dev-ai review this PR

cubic-dev-ai · 2026-09-24T19:13:34Z

@cubic-dev-ai review this PR

@BillLeoutsakosvl346 I have started the AI code review. It will take a few minutes to complete.

greptile-apps · 2026-09-24T19:16:58Z

Confidence Score: 5/5

The PR appears safe to merge.

Summary

The PR moves the shared shimmer treatment into EMCN and updates activity status, agent-stream chrome, and the thinking loader to use it.

The change since the previous review replaces the chat-message test’s real-module mock with explicit exports.
No new actionable issue was identified.

Diagram

%%{init: {'theme': 'neutral'}}%%
flowchart LR
  S[EMCN ShimmerText] --> A[Activity status]
  S --> C[Agent-stream chrome]
  S --> T[Thinking loader]

_{Reviews (5) · Last reviewed commit: "test(chat): mock EMCN exports explicitly"}

cubic-dev-ai

No issues found across 12 files

Confidence score: 5/5

Automated review surfaced no issues in the provided summaries.
No files require special attention.

_{Re-trigger cubic}

cubic-dev-ai

No issues found across 12 files

Confidence score: 5/5

Automated review surfaced no issues in the provided summaries.
No files require special attention.

_{Re-trigger cubic}

BillLeoutsakosvl346 · 2026-09-24T19:18:53Z

@greptile review this updated commit

BillLeoutsakosvl346 · 2026-09-24T19:18:57Z

@cubic-dev-ai review this updated commit

cubic-dev-ai · 2026-09-24T19:19:09Z

@cubic-dev-ai review this updated commit

@BillLeoutsakosvl346 I have started the AI code review. It will take a few minutes to complete.

cubic-dev-ai

No issues found across 12 files

Confidence score: 5/5

Automated review surfaced no issues in the provided summaries.
No files require special attention.

_{Re-trigger cubic}

BillLeoutsakosvl346 · 2026-09-24T19:24:39Z

@greptile review this updated commit

BillLeoutsakosvl346 · 2026-09-24T19:24:43Z

@cubic-dev-ai review this updated commit

cubic-dev-ai · 2026-09-24T19:24:58Z

@cubic-dev-ai review this updated commit

@BillLeoutsakosvl346 I’ve started reviewing the changes since the last completed review. I’ll post the results here when it’s done.

cubic-dev-ai

0 issues found across 1 file (changes from recent commits).

_{Re-trigger cubic}

BillLeoutsakosvl346 · 2026-09-25T00:01:46Z

Visual review: shared shimmer text

Change. The app-local ShimmerText moves into EMCN. Activity status and agent-stream imports point to the shared export, while ThinkingLoader uses that same component for its active label. The loader's nonshimmer static label stays separate. The gradient, 2.2s timing, text geometry, dark treatment, and reduced-motion fallback are preserved.

Source-exact ThinkingLoader excerpts (other consumers switch their ShimmerText import from the app module to @sim/emcn):

Before

<span className={shimmer ? styles.label : styles.labelStatic}>{shownLabel}</span>

After

{shimmer ? (
  <ShimmerText className={styles.label}>{shownLabel}</ShimmerText>
) : (
  <span className={styles.labelStatic}>{shownLabel}</span>
)}

Images. Each image is a labeled isolated render of the real before/after product compositions using compiled product CSS. Before is left; After is right. It covers ThinkingLoader, ActivityStatus, and agent-stream thinking. The earlier follow-up commits add tests. The staging merge preserves the shared shimmer renderer and CSS; staging also changed the active label wording to “Thinking” in both base and head. These captures document the shimmer treatment and geometry, while their text may show the earlier wording.

Mode	Light 16px	Dark 16px	Light 20px	Dark 20px
Normal motion
Reduced motion

Staging conflict resolution · `cbbb28d930`

Staging edited a JSDoc sentence in the app-local shimmer-text.tsx that this PR removes. The resolution keeps the deletion and the EMCN export; no second implementation remains. The Thinking wording change came from staging and is present on both sides of the current comparison. Focused app and EMCN tests (44), both type checks, and the local design diff check pass with no new findings.

Review follow-up · de0a95ee5e: The latest commit replaces a test mock that loaded the real EMCN module with explicit mocked exports. It changes no product component, CSS, or visual state shown above.

BillLeoutsakosvl346 · 2026-09-25T00:44:20Z

@greptileai review this PR

BillLeoutsakosvl346 · 2026-09-25T00:44:22Z

@cubic-dev-ai review this PR

cubic-dev-ai · 2026-09-25T00:44:30Z

@cubic-dev-ai review this PR

@BillLeoutsakosvl346 I have started the AI code review. It will take a few minutes to complete.

cubic-dev-ai

No issues found across 13 files

Confidence score: 5/5

Automated review surfaced no issues in the provided summaries.
No files require special attention.

_{Re-trigger cubic}

BillLeoutsakosvl346 · 2026-09-25T00:56:25Z

@greptileai review this PR

BillLeoutsakosvl346 · 2026-09-25T00:56:26Z

@cubic-dev-ai review this PR

cubic-dev-ai · 2026-09-25T00:56:30Z

@cubic-dev-ai review this PR

@BillLeoutsakosvl346 I have started the AI code review. It will take a few minutes to complete.

cubic-dev-ai

No issues found across 13 files

Confidence score: 5/5

Automated review surfaced no issues in the provided summaries.
No files require special attention.

_{Re-trigger cubic}

Preserve staging deletions of the tool-call-item and agent-stream-chrome tests. Retain the shared EMCN shimmer component migration and current thinking-loader behavior.

refactor(emcn): own shared shimmer text treatment

7108d6e

vercel Bot deployed to Preview September 24, 2026 19:15 View deployment

greptile-apps Bot reviewed Sep 24, 2026

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Comment thread packages/emcn/src/components/shimmer-text/shimmer-text.test.tsx

cubic-dev-ai Bot reviewed Sep 24, 2026

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test(emcn): assert shimmer class wiring

8d9f48c

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cubic-dev-ai Bot reviewed Sep 24, 2026

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test(chat): preserve EMCN exports in message mock

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vercel Bot temporarily deployed to Preview September 24, 2026 19:24 Inactive

cubic-dev-ai Bot reviewed Sep 24, 2026

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Merge staging into shared shimmer treatment

cbbb28d

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greptile-apps Bot reviewed Sep 25, 2026

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Comment thread apps/sim/app/(interfaces)/chat/components/message/message.test.tsx Outdated

test(chat): mock EMCN exports explicitly

de0a95e

vercel Bot temporarily deployed to Preview September 25, 2026 00:55 Inactive

cubic-dev-ai Bot reviewed Sep 25, 2026

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Merge staging into codex/emcn-next-shimmer-text

8f5e21b

Preserve staging deletions of the tool-call-item and agent-stream-chrome tests. Retain the shared EMCN shimmer component migration and current thinking-loader behavior.

vercel Bot deployed to Preview October 3, 2026 03:25 View deployment

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Visual review: shared shimmer text

Staging conflict resolution · cbbb28d930

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Staging conflict resolution · `cbbb28d930`