Implement the following plan:

Semester-Wide Partner Rotation with Recency-Based Window

Goal

Replace per-groupKey partner tracking with semester-wide, recency-based tracking. Students get graduated friction when pairing with recent partners: strong friction for their most recent partner (two-step confirm), soft warnings for other recent partners within a window, and no warning beyond the window.

Design

Recency Ranking

Instead of counting raw pairing occurrences, rank each prior partner by how recently the student last worked with them across ALL group activities in the semester:

• Rank 1: Most recent partner (last person they worked with)
• Rank 2: Second most recent, etc.

Window Size

Window = max(3, floor(sqrt(enrolled_students))) where enrolled students is queried from the enrollments table (active students in the semester).

• 100 students → window 10
• 25 students → window 5
• 9 students → window 3

Friction Levels

Current Flow (for reference)

• getPriorPartnerCounts() (line 506) filters by groupKey, returns Record<string, number> (userId → count)
• GET endpoint (line 163) returns priorPartnerCounts map to client
• POST join endpoint (line 274) checks count, always performs the join, returns priorPairingCount in response
• Client shows warning cosmetically after join has already happened (line 375)

Changes

1. Replace getPriorPartnerCounts() with getPartnerRecency()

File: apps/api/src/routes/group-activities.ts (~line 506)

Replace the function with:

async function getPartnerRecency(
  userId: string,
  currentActivityId: string,
  semester: string
): Promise<Record<string, number>>

Returns Record<string, number> mapping partnerId → recency rank (1 = most recent).

Query logic:

1. Find all groups where user is a member with joinedAt set, in this semester, excluding current activity
2. For each group, find other members (also with joinedAt set)
3. For each partner, take their most recent joinedAt across all shared groups
4. Order by most recent first, assign ranks 1, 2, 3...

No longer filters by groupKey — uses only semester and activityId.

2. Add getEnrollmentWindowSize() helper

File: apps/api/src/routes/group-activities.ts

async function getEnrollmentWindowSize(semester: string): Promise<number> {
  const [result] = await db
    .select({ count: count() })
    .from(enrollments)
    .where(
      and(
        eq(enrollments.semester, semester),
        eq(enrollments.enrollmentType, "student"),
        eq(enrollments.isActive, true)
      )
    );
  return Math.max(3, Math.floor(Math.sqrt(result?.count ?? 0)));
}

3. Update GET endpoint

File: apps/api/src/routes/group-activities.ts (~line 163)

• Call getPartnerRecency() instead of getPriorPartnerCounts() (drop groupKey param)
• Also call getEnrollmentWindowSize()
• Return priorPartnerRecency (rank map) and windowSize instead of priorPartnerCounts

4. Update POST join endpoint — two-step confirm for rank 1

File: apps/api/src/routes/group-activities.ts (~line 209-443)

• Add confirmPriorPartner boolean to join request schema (default false)
• After finding the partner membership, call getPartnerRecency() and getEnrollmentWindowSize()
• Look up the partner's recency rank
• Rank 1 + !confirmPriorPartner: Return early WITHOUT performing the join:

  { "success": false, "requiresConfirmation": true, "recencyRank": 1, "partnerName": "...", "windowSize": N }
  

• Rank 1 + confirmPriorPartner: Perform the join, return { "success": true, "recencyRank": 1, ... }
• Rank 2-N within window: Perform the join, return { "success": true, "recencyRank": N, "partnerName": "...", "windowSize": N }
• Beyond window or no prior: Perform the join, return { "success": true }

5. Update client join response types and warning UI

File: apps/web/components/mdx/group-activity-client.tsx

Types (~line 149):

• Replace priorPairingCount?: number with recencyRank?: number, windowSize?: number, requiresConfirmation?: boolean in JoinResponse
• Replace priorPartnerCounts: Record<string, number> with priorPartnerRecency: Record<string, number> and windowSize: number in GroupStatusResponse

Warning state (~line 187):

• Change from { count, name, code } to { recencyRank, name, code, confirmed: boolean }
• confirmed tracks whether user has re-entered the code (for rank 1 two-step)

Join handler (~line 322):

• On requiresConfirmation: true (rank 1, first attempt): set warning state with confirmed: false, clear code input. No "Join anyway" button shown.
• When user re-enters the same code and it matches the warning state code: set confirmed: true, show "Join anyway" button.
• Clicking "Join anyway": call handleJoin with confirmPriorPartner: true
• On rank 2-N within window (join succeeded): show soft dismissible warning, no action needed.

Warning UI (~line 579):

• Rank 1 (not confirmed): Strong message: "You just worked with [name]! Please find a different partner." No join button. Code input cleared.
• Rank 1 (confirmed, code re-entered): Same strong message + "Join anyway" button.
• Rank 2-N within window: Soft message: "You've worked with [name] recently. Try meeting someone new next time!" with "OK" dismiss button (join already succeeded).

6. Add third test page with different groupKey

File: apps/web/app/testing/components/group-activity-3/page.tsx (new)

import { GroupActivity } from "@/components/mdx/group-activity";

export default function TestGroupActivity3() {
  return (
    <div data-testid="test-page" className="p-6">
      <h1 className="mb-6 text-2xl font-bold">Group Activity Test (Different Key)</h1>
      <GroupActivity id="third-activity" group="test-meeting-OTHER" size={2}>
        <div className="rounded border border-purple-500/50 bg-purple-500/10 p-4">
          <h2 className="mb-2 font-semibold">Third Activity Content!</h2>
          <p>This activity has a different group key for cross-key partner tracking tests.</p>
        </div>
      </GroupActivity>
    </div>
  );
}

7. Update E2E tests

File: testing/e2e/tests/group-activity.spec.ts

Update existing "Partner Rotation" test (~line 131):

• Update assertions to match new warning text ("just worked with" instead of "already worked with ... today")
• For rank 1 (immediate repeat): verify NO "Join anyway" button on first attempt, re-enter code, verify button appears, click it

Add new test: "cross-groupKey partner tracking":

• Pair student1 and student2 in group-activity (groupKey test-meeting-2026-01-25)
• Navigate both to group-activity-3 (groupKey test-meeting-OTHER)
• Student2 enters student1's code → verify rank 1 warning appears despite different groupKey
• Verify two-step confirm flow works

Verification

# Run the specific test
cd testing/e2e && CI=true bunx playwright test --project=group-activity

# Run full suite
CI=true bun run test:e2e

If you need specific details from before exiting plan mode (like exact code snippets, error messages, or content you generated), read the full transcript at: ~/.claude/projects/-Users-challen-www-usingandunderstanding-ai/d679d4da-a306-4569-b2f3-ffb567cfd742.jsonl

Your task

First, run git status, git diff, and git log --oneline -10 to understand the current state.

Then add and commit all modified files with a descriptive message. Break the changes into multiple commits if appropriate. If there are untracked files, ask if they should be added or added to the appropriate .gitignore file. The user may also want to take over at this point, so provide an abort option as well. Always check changes for unnecessary debugging statements or logging that might have been accidentally included. Prompt the user if you find any, and offer to remove each one by one. Do not use interactive git staging (git add -p) as it does not work.

For the GPT models on the chat page, can we configure their context window length? That might be helpful for exploration, particularly creating small windows.

Can we control this on the message level? That would be cool!