feat(tui): configurable frequency or opt-out for system reminders (TodoList / permission-mode / AGENTS.md / date)

[wubing-wx]

Summary

The four built-in system reminders currently have no user-facing frequency control or opt-out. Measured over 7 days of real session transcripts, they independently triggered 1,376 extra LLM turns — about 13% of all LLM calls in that window.

Measured impact (7 days, 228 real session transcripts, offline wire.jsonl analysis)

System-injected turns, classified into three buckets:

bucket	turns / 7d	contents	verdict
A. Must wake the model	140	background task / subagent completion notifications	keep as-is
B. Mergeable reminders	948	TodoList stale reminder 426 · auto-permission-mode reminder 390 · AGENTS.md path reminders ~106 · interruption reminder 16	same-variant reminder repeats within one session — merge to first occurrence
C. Doesn't need the model at all	323	"Today's date is …" 305 · image-compression notices · plugin-installed notices	persist to log, don't inject

97–99% of these turns independently trigger a new LLM request (verified in wire transcripts: the reminder message is immediately followed by an llm.request with no real user message in between). Buckets B + C alone account for ≥1,238 avoidable LLM calls per 7 days (~13% of total) — and each extra turn also busts the prompt prefix cache (new turn = full uncached recompute for large prefixes).

Current behavior (source pointers, 0.40.x)

• TodoList reminder: hard-coded constants TODO_LIST_REMINDER_TURNS_SINCE_WRITE = 10 / TODO_LIST_REMINDER_TURNS_BETWEEN_REMINDERS = 10 in packages/agent-core-v2/src/features/todo/todoListReminder.ts:7-8
• permission-mode reminder: event-triggered injection, no frequency config (agent/permissionMode/injection/)
• AGENTS.md reminder: path-triggered, no config (agent/agentsMdReminder/)
• date-change reminder: startup + date-change injection, no config (features/dateChange/dateChangeService.ts)
• IAgentReminderService.register(variant, provider) has no user-facing configuration surface — each provider's cadence is baked into code

Proposed

Per-variant configuration — interval in turns, or off — e.g. in tui.toml:

[reminders]
todo_list = 50            # turns between reminders; 0 = off
permission_mode = "change-only"
agents_md = "once-per-session"
date_change = "off"

Even a single global "reminder interval multiplier / master switch" would already recover most of the cost.

Notes

• We are not asking to remove the reminders — the TodoList reminder is genuinely useful. The issue is frequency and the inability to tune it.
• The 7-day measurement method (offline wire.jsonl turn classification) is available on request.