feat(context-window-monitor): add progressive warnings at 50%, 60%, 70%, 80%

[taetaetae]

Summary

Add stepped context window warnings instead of a single 70% threshold notification.

Changes

• Replace single 70% threshold with progressive warnings at 50%, 60%, 70%, 80%
• Add ANSI color coding for visual urgency differentiation:
  • 📊 50% (INFO) - Blue
  • 📈 60% (NOTICE) - Yellow
  • ⚠️ 70% (WARNING) - Orange
  • 🚨 80% (CRITICAL) - Red
• Track notified thresholds per session to avoid duplicate alerts at the same level
• Each threshold triggers once with appropriate urgency messaging

Motivation

Previously, users only received a single notification at 70% context usage. By the time they noticed, it was often too late to wrap up work before hitting the 80%+ limit where sessions can become unresponsive.

With progressive warnings, users get early awareness (50%, 60%) and can plan accordingly, with increasingly urgent notifications as context fills up.

Testing

• bun run typecheck passes
• bun run build succeeds
• Tested locally with OpenCode

Screenshots

N/A (terminal color output)

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Summary by cubic

Replace the single 70% context alert with progressive warnings at 50%, 60%, 70%, and 80% to give earlier, clearer signals. Adds color-coded urgency and triggers each level only once per session.

• New Features
  • Stepped thresholds: 50% INFO (blue), 60% NOTICE (yellow), 70% WARNING (orange), 80% CRITICAL (red).
  • Higher-level triggers mark lower levels to prevent out-of-order alerts; cleanup on session deletion.
  • Colored status line shows used/remaining tokens; guarded for Anthropic and degrades gracefully on errors.

^{Written for commit a0ded61. Summary will update on new commits.}

[github-actions]

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[cubic-dev-ai]

1 issue found across 1 file

Confidence score: 4/5

• This PR looks safe to merge with low risk; the single issue is moderate severity (4/10) and mainly affects warning ordering rather than core functionality.
• In src/hooks/context-window-monitor.ts, skipped thresholds can lead to lower-urgency warnings firing after a critical warning, which may confuse users monitoring usage levels.
• Pay close attention to src/hooks/context-window-monitor.ts - threshold notification order and backfilled warnings.

Prompt for AI agents (all issues)

Check if these issues are valid — if so, understand the root cause of each and fix them.


<file name="src/hooks/context-window-monitor.ts">

<violation number="1" location="src/hooks/context-window-monitor.ts:122">
P2: Only the highest threshold is marked as notified, so if usage skips thresholds (e.g., 40% → 80%), subsequent runs will emit lower-urgency warnings after the critical warning. This creates out-of-order backfilling of alerts and likely defeats the intended progressive warning behavior.</violation>
</file>

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[taetaetae]

Thanks @cubic-dev-ai for catching this issue!

Fixed in the latest commit - now when a threshold is triggered, all lower thresholds are also marked as notified. This prevents out-of-order warnings when usage jumps (e.g., 40% → 80%).