feat(web): choose the first day of the week

[id0Sch]

Problem

"Next week" in the snooze menu always lands on Monday 9:00. Teams whose work week starts on Sunday (Israel and much of the Middle East, for example) have no way to change that, and the Custom… snooze calendar's first day follows only the OS or browser locale.

Change

Adds a First day of the week setting under Settings → General with three options: System default, Sunday, Monday. It's a local client setting, like Time format.

• Sunday / Monday: "Next week" wakes on that day at 9:00, and the Custom… calendar starts on it.
• System default: today's behavior is unchanged. The calendar follows the locale (fix(web): the custom snooze calendar starts the week where the locale does #12745) and "Next week" stays on Monday. Calendar week start and the start of the work week differ: en-US calendars start on Sunday, but sending every US user's snooze to Sunday morning would be wrong.
• The shared resolveSnoozePresets takes an optional weekStartsOn, defaulting to Monday. As today, "Next week" is hidden when it would land on the same morning as "Tomorrow", which with Sunday weeks means on Saturdays.
• Mobile keeps Monday. It has no local client-settings store to read this from, and the shared default keeps its behavior identical.
• The setting is searchable, has a reset button, is covered by Restore defaults, and has one line in the snooze section of docs/user/thread-sidebar.md.

Scope and approval

This is a focused configuration option for an established capability. Week start already exists: the snooze calendar reads it from the locale, and "Next week" hard-codes Monday. The option only picks which day both use. It adds no workflow, and the default behaves exactly as before. Proposed in Ideas #14633, which has no maintainer reply yet. #9011 tried a locale-only version and was closed for missing UI evidence; that evidence is below.

Verification

• vp test run on Sidebar.snooze.test.ts, timestampFormat.test.ts, settingsSearch.test.ts, threadSnoozed.test.ts and mobile threadListV2.test.ts: 230 passed. New cases cover a Sunday week start (Friday → Sunday, and "Next week" hidden on Saturday) and the explicit setting overriding the locale for the calendar.
• Typecheck is clean for contracts, client-runtime, web and mobile.
• Manual check in the web client against isolated dev state, with headless Chromium and the page clock pinned to Wednesday, Oct 7, 10:00. Each run opened the snooze menu, picked Next week, and read the Snoozed shelf's wake label:

	Monday (same as current behavior)	Sunday
Snooze menu
After snoozing "Next week"

The Custom… calendar, opened from the same snooze menu with each setting (en-US browser locale; the explicit setting overrides it):

Monday	Sunday

Model: Claude Opus 5.5. Harness: Claude Code in T3 Code.

🤖 Generated with Claude Code

[macroscopeapp]

Approvability

Verdict: Not approved

Macroscope's review found this PR not approvable — This PR adds a persisted user-facing setting that changes both calendar layout and the actual Next week snooze date across several web and shared-runtime paths. The default preserves current behavior, but the cross-cutting capability and new settings contract warrant human review.

^{You can add or adjust custom eligibility rules. Learn more.}

[coderabbitai]

Important

Review skipped

We couldn't safely recover the incremental review. No full review was started, and the last reviewed checkpoint was preserved. Retry later, or explicitly request a full review by commenting @coderabbitai full review.

You can disable this status message by setting the reviews.review_status to false in the CodeRabbit configuration file.

Use the checkbox below for a quick retry:

• 🔍 Trigger review

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

• Configuration used: Repository: pingdotgg/t3code/.coderabbit.yaml
• Review profile: CHILL
• Plan: Advanced
• Run ID: 60f8edca-9896-4d82-8ce5-ec8e9c4b22ba

📥 Commits

Reviewing files that changed from the base of the PR and between 13b780a and 2d1b59f.

📒 Files selected for processing (4)

• apps/web/src/components/Sidebar.tsx
• apps/web/src/components/settings/SettingsPanels.tsx
• docs/user/thread-sidebar.md
• packages/contracts/src/settings.ts

🚧 Files skipped from review as they are similar to previous changes (1)

• docs/user/thread-sidebar.md

Included review availability: This review used your included allowance. Your plan provides up to 10 included reviews per hour; 8 remain after this review.

📝 Walkthrough

Adds a configurable first-day-of-week preference with locale, Sunday, and Monday choices. Calendar layout and snooze presets use the preference. The “Next week” preset defaults to Monday.

Changes: First-Day-of-Week Preference

Layer / File(s)	Summary
Define and expose the preference packages/contracts/src/settings.ts, apps/web/src/components/settings/SettingsPanels.tsx, apps/web/src/components/settings/settingsSearch.ts	Adds the preference to client settings and patches. General settings offers locale, Sunday, and Monday choices, supports restoring the default, and includes a searchable entry.
Resolve calendar and snooze week starts apps/web/src/timestampFormat.ts, apps/web/src/timestampFormat.test.ts, packages/client-runtime/src/state/threadSettled.ts, packages/client-runtime/src/state/threadSnoozed.test.ts	Adds calendar and snooze week-start conversion functions. The shared resolver uses the supplied weekday for “Next week,” with Monday as its default. Tests cover explicit week starts.
Use the preference in calendars and snooze menus apps/web/src/components/CustomSnoozeDialog.tsx, apps/web/src/components/Sidebar.snooze.ts, apps/web/src/components/Sidebar.snooze.test.ts, apps/web/src/components/Sidebar.tsx, apps/web/src/hooks/useThreadActionMenu.ts, docs/user/thread-sidebar.md	Passes the configured preference to custom calendar and snooze menu calculations. Tests cover Sunday-based presets. Documentation describes the setting and “Next week” wake timing.

Priority: ➖ Normal

Estimated code review effort: 3 (Moderate) | ~20 minutes

Change: Feature

Sequence Diagram(s)

sequenceDiagram
  participant ClientSettings
  participant Sidebar
  participant resolveSnoozePresets
  participant CustomSnoozeDialog
  participant calendarWeekStartsOn
  ClientSettings->>Sidebar: provide firstDayOfWeek
  Sidebar->>resolveSnoozePresets: pass converted snooze week start
  CustomSnoozeDialog->>ClientSettings: read firstDayOfWeek
  CustomSnoozeDialog->>calendarWeekStartsOn: resolve calendar week start

Loading

Suggested reviewers: juliusmarminge

Merge Risk: ⚪ Minimal · up to 2d1b5

No actionable issue is established for the new week-start setting; the PR is mergeable after normal checks.

Security Architecture Review

Security architecture risk: ⚪ Minimal · up to 2d1b5

The preference changes calendar layout and proposed snooze dates without expanding access or changing thread-action authority. Existing defaults and failure-handling paths are preserved. No material security risk was found in the reviewed change.

Retained concerns
No architecture-level concerns identified.

Security review details

Security Blast Radius

• inferred — The added preference affects calendar presentation and wake timestamps for threads selected through existing actions. It does not expand the thread-selection or environment-targeting scope: preset handlers continue forwarding the same scoped thread reference.

Trust Boundaries and Controls

• observed — The existing snooze action checks environment support and blocked or queued thread state before dispatch. The command continues carrying environment and thread identity; the new preference only supplies the wake timestamp. Server-side authorization enforcement was not independently traced.

Resilience and Maintainability Implications

• observed — The changed entrypoints retain per-thread duplicate guards and serialized command execution. Failure and interruption remain on existing cleanup paths, successful actions register scoped unsnooze recovery, and bulk operations distinguish per-thread outcomes. These mechanisms predate the PR and were not replaced by the preference change.

Pre-merge checks: 4 · 1

Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage		Docstring coverage is 50.00% which is insufficient. The required threshold is 80.00%. Docstring coverage is scoped to functions touched by this diff. Analyzed 12 functions across 12 files. (1 skipped:…	Write docstrings for the functions missing them to satisfy the coverage threshold.

Passed checks (4 passed)

Check name	Status	Explanation
Linked Issues check		Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check		Check skipped because no linked issues were found for this pull request.
Title check		The title clearly and concisely describes the primary change: adding a web setting to choose the first day of the week.
Description check		The description includes all required sections, explains the problem and change, documents scope and approval context, and provides focused test results, typecheck results, manual verification, screen…

Full details: Docstring Coverage

Explanation

Docstring coverage is 50.00% which is insufficient. The required threshold is 80.00%. Docstring coverage is scoped to functions touched by this diff. Analyzed 12 functions across 12 files. (1 skipped: 1 unsupported.)

✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create a new PR

• Autopilot · Keep fixing CodeRabbit findings and required CI, and resolving merge conflicts

_{Comment @coderabbitai help to get the list of available commands.}

[id0Sch]

@juliusmarminge @maria-rcks could one of you take a look when you have a moment? Thanks, I appreciate your time.

[juliusmarminge]

Note

This comment is posted by Julius' dot

The snooze screenshots show the Monday/Sunday change and resulting wake dates. Please also add screenshots of the Custom calendar before and after changing the first weekday from Monday to Sunday. Its week layout changes too, and helper tests do not replace the required UI evidence.

[id0Sch]

Note

This comment is posted by Julius' dot

The snooze screenshots show the Monday/Sunday change and resulting wake dates. Please also add screenshots of the Custom calendar before and after changing the first weekday from Monday to Sunday. Its week layout changes too, and helper tests do not replace the required UI evidence.

On it. thanks!

[id0Sch]

@juliusmarminge added Custom… calendar screenshots for Monday and Sunday to the description, under Verification. Thanks!

[id0Sch]

@juliusmarminge hate to bother you, but wdyt? i encounter it daily on thursdays and it make me miss stuff on sunday lol