Greptile Summary

This PR fixes a false-positive "100% context used" warning in the chat view by switching from the accumulated inputTokens counter to the gateway-persisted totalTokens snapshot as the basis for context-usage calculation, and suppressing the warning entirely when that snapshot is marked stale (totalTokensFresh === false).

• ui/src/ui/types.ts: Adds the totalTokensFresh?: boolean field to GatewaySessionRow, aligning the UI type with the backend session types.
• ui/src/ui/views/chat.ts: renderContextNotice now uses totalTokens (fresh context size) instead of inputTokens (cumulative), and returns nothing when the cached snapshot is stale — preventing misleading banners during active tool loops.
• ui/src/ui/views/chat.test.ts: Two new negative-case tests guard the fix, but a positive-case test (warning appears when totalTokensFresh: true and totalTokens is above the 85% threshold) is missing, leaving a potential blind spot for future regressions.

Confidence Score: 4/5

• Safe to merge; the logic fix is correct and well-aligned with the gateway's token freshness semantics.
• The one-line change in chat.ts is clearly correct — totalTokens reflects the live context size and the gateway already normalizes totalTokensFresh to true/false before sending it to the UI, so the undefined edge case is benign. The only gap is the absence of a positive test asserting the warning still fires under the right conditions, which slightly lowers confidence that a future accidental no-op won't regress silently.
• No files require special attention; the test file could benefit from an additional positive-case assertion.

This is a comment left during a code review.
Path: ui/src/ui/views/chat.test.ts
Line: 252-307

Comment:
**Missing positive-case test for context warning**

Both new tests only verify that the warning is *suppressed*. There is no test asserting that the warning *does* appear when `totalTokensFresh` is `true` (or unset) and `totalTokens` is above the 85% threshold. Without a positive case, a future regression that accidentally sets `used = 0` unconditionally would go undetected.

Consider adding a test like:

```ts
it("shows the context warning when totalTokensFresh is true and total tokens exceed threshold", () => {
  const container = document.createElement("div");
  render(
    renderChat(
      createProps({
        sessions: {
          ts: 0,
          path: "",
          count: 1,
          defaults: { modelProvider: "openai", model: "gpt-5", contextTokens: 128_000 },
          sessions: [
            {
              key: "main",
              kind: "direct",
              updatedAt: null,
              totalTokens: 115_000,
              totalTokensFresh: true,
              contextTokens: 128_000,
            },
          ],
        },
      }),
    ),
    container,
  );
  expect(container.textContent).toContain("context used");
});
```

How can I resolve this? If you propose a fix, please make it concise.

_{Last reviewed commit: 78281d2}

Closing as superseded by #71297. Both PRs address the same Control UI chat warning bug tracked by #49076: stale or cumulative context measurements causing misleading 100% context used UI.

#71297 is the current canonical fix because it also applies live session metadata from gateway events, coalesces overlapping session refreshes so the value does not remain stale under chat churn, suppresses totalTokensFresh=false snapshots, and adds focused coverage for those behaviors.