[FEATURE] context-health monitoring

Preflight Checklist

• [x] I have searched existing requests and this feature hasn't been requested yet
• [x] This is a single feature request (not multiple features)

Problem Statement

(applies to Chat UI and TUI)

At some point during a conversation, earlier replies from the model or the user are no longer available to the model resulting in a mismatch in context between the user and the model. The user believes their reply is clear based upon their earlier conversation and the model silently doesn't remember that the earlier conversation ever existed.

The only user-available workaround is an in-band ledger, and that it doesn't even work, because this surface preserves HTML comments but renders them visibly.

Proposed Solution

Expose, natively and to both the user and the model, (1) per-turn model identity, (2) context occupancy or position in the window, and (3) a truncation flag when earlier turns fall out of context — so neither party has to improvise an in-band ledger to know the state of the channel they're talking over.

Alternative Solutions

_No response_

Priority

Critical - Blocking my work

Feature Category

CLI commands and flags

Use Case Example

_No response_

Additional Context

_No response_