[Bug] TodoWrite reminders degrade context retrieval in long sessions; no disable option

Bug Description
Subject: TodoWrite nag reminders degrade long-session reliability — no way to suppress

Impact: During a multi-hour infrastructure migration session (server decommissioning, DNS changes, database migrations, Docker builds), the model completely lost track of work it had done earlier in the same session — including an IP address it had itself resolved and stated. The transcript on disk confirmed the information was in the session, uncompacted. The model failed to retrieve it from its own context.

Investigation revealed repeated system-reminder injections throughout the session:

TodoWrite nag reminders injected 4+ times, each instructing the model to hide the reminder from the user
Deferred tools listings re-injected with ~200+ tool names
MCP server instructions re-injected on tab switch (sessionStart hook appears to re-fire in Claude Desktop on tab changes)
Skills inventory re-injected
These injections accumulate in the context window and appear to contribute to "lost in the middle" attention degradation, pushing earlier conversation content below the model's effective retrieval threshold.

Specific concerns:

TodoWrite nags are unsuppressible — no setting exists to disable them (confirmed via issues #9769, #6760, #4464)
The nag instructs the model to deceive the user — "Make sure that you NEVER mention this reminder to the user" is a hostile design choice
Re-injection on tab switch — sessionStart-triggered content re-injects on every Claude Desktop tab switch, not just actual session starts
No priority system — Anthropic's TodoWrite feature competes equally with the user's actual work context for attention. The system is treating its own feature promotion as equal priority to critical operational data.
Real-world cost: Lost track of a server IP mid-migration, attempted to SSH to wrong servers, repeated work already done, ~30 minutes wasted on a live infrastructure operation. The model had the information in context but couldn't retrieve it.

Request: Add a setting to disable TodoWrite reminders (and ideally all periodic system reminders). Users running complex multi-hour sessions with many MCP servers need their context window for actual work, not feature promotion.

References: #9769, #6760, #4464, #21693

Environment Info

• Platform: darwin
• Terminal: Apple_Terminal
• Version: 2.1.87
• Feedback ID: 63c0bb33-41c9-4fc7-9ce6-3b63aefee830

Errors

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