Provider model context windows now feed the composer-level context indicator, so users can see current usage without opening slash panels. The indicator refreshes when the session runtime model changes, keeps a stable loading placeholder, and marks estimate fallback data during reconnect or compaction windows.
Constraint: The desktop UI must use the real session inspection API and session-scoped runtime selection instead of mocked or static context values.
Rejected: Keep context details only in /context or /status | the user explicitly wanted an always-visible composer indicator.
Rejected: Reuse stale context after model switches | different provider windows make identical percentages misleading.
Confidence: high
Scope-risk: moderate
Directive: Do not remove the runtimeSelectionKey refresh path without real multi-provider browser verification.
Tested: cd desktop && bun run test -- pages.test.tsx
Tested: bun run check:desktop
Tested: KEEP_ARTIFACTS=1 desktop/scripts/e2e-context-usage-live-agent-browser.sh
Not-tested: Live browser E2E with every configured provider in the committed script; separate agent-browser sweep verified four providers locally.
