diff --git a/packages/zcode-tui/src/context-status-view.ts b/packages/zcode-tui/src/context-status-view.ts
index cd76e98..e824cd0 100644
--- a/packages/zcode-tui/src/context-status-view.ts
+++ b/packages/zcode-tui/src/context-status-view.ts
@@ -11,7 +11,7 @@ import type {
   RuntimeProjectionSnapshot
 } from "./runtime-projection.ts";
 import type { ContextCacheTrend, ContextCacheTurn } from "./context-cache.ts";
-import type { SessionMetrics } from "./session-status.ts";
+import { contextUsedPercent, type SessionMetrics } from "./session-status.ts";
 import type { ZCodeTheme } from "./theme.ts";
 
 const contextLabels: Record<RuntimeContextBreakdownItem["source"], string> = {
@@ -156,7 +156,10 @@ export class ContextDetailView implements Component {
       const columns = totalChars > 0 ? Math.max(1, Math.round(item.chars / totalChars * barWidth)) : 0;
       return contextStyle(item.source, this.theme)("█".repeat(columns));
     }).join("");
-    const usedPercent = Math.max(0, Math.round(this.usage.used / this.usage.size * 100));
+    const usedPercent = contextUsedPercent({
+      contextUsed: this.usage.used,
+      contextWindow: this.usage.size
+    }) ?? 0;
     const remaining = Math.max(0, this.usage.size - this.usage.used);
     const usageStyle = usedPercent >= 90 ? this.theme.error : usedPercent >= 70 ? this.theme.warning : (text: string) => text;
     const lines = [
@@ -306,7 +309,7 @@ export class StatusDetailView implements Component {
         ? [projection.lastError.code, projection.lastError.message].filter(Boolean).join(" · ")
         : undefined],
       ["Turns", String(metrics.turnCount ?? projection?.turnCount ?? 0)],
-      ["Tokens", metrics.totalTokens !== undefined ? formatTokens(metrics.totalTokens) : undefined],
+      ["Session tokens", metrics.totalTokens !== undefined ? formatTokens(metrics.totalTokens) : undefined],
       ["Requests", metrics.modelRequestCount !== undefined
         ? `${metrics.modelRequestCount}${metrics.modelErrorCount ? ` · ${metrics.modelErrorCount} errors` : ""}`
         : undefined],
diff --git a/packages/zcode-tui/src/index.ts b/packages/zcode-tui/src/index.ts
index aeee016..1ec3d40 100644
--- a/packages/zcode-tui/src/index.ts
+++ b/packages/zcode-tui/src/index.ts
@@ -162,6 +162,7 @@ import {
 import {
   contextRemainingPercent,
   mergeMetrics,
+  mergeProjectionMetrics,
   projectionMetrics,
   sessionIdFromUsage,
   usageMetrics,
@@ -1447,7 +1448,11 @@ class ZCodeTui {
     }
     if (Array.isArray(result.modelOptions)) this.modelOptions = [...result.modelOptions];
     if (Array.isArray(result.effortOptions)) this.effortOptions = [...result.effortOptions];
-    this.sessionMetrics = mergeMetrics(this.sessionMetrics, projectionMetrics(result.projection));
+    this.sessionMetrics = mergeProjectionMetrics(
+      this.sessionMetrics,
+      projectionMetrics(result.projection),
+      Boolean(this.options.readSessionUsage)
+    );
     if (Array.isArray(result.todos)) this.todos = normalizeTodos(result.todos);
     if (Array.isArray(result.todoGroups)) this.todoGroups = normalizeTodoGroups(result);
     this.applyRuntimeProjection(normalizeRuntimeProjection(result));
@@ -3950,8 +3955,8 @@ class ZCodeTui {
     if (this.sessionMetrics.totalTokens !== undefined) {
       const tokens = formatTokens(this.sessionMetrics.totalTokens);
       fields.push({
-        text: this.theme.muted(`${tokens} tokens`),
-        compactText: this.theme.muted(`${tokens} tok`),
+        text: this.theme.muted(`session ${tokens} tokens`),
+        compactText: this.theme.muted(`session ${tokens}`),
         priority: 20
       });
     }
@@ -4064,12 +4069,16 @@ class ZCodeTui {
     this.runtimeProjection = projection;
     this.reconcileTurnTiming(projection);
     if (projection.sessionId) this.sessionId = projection.sessionId;
-    this.sessionMetrics = mergeMetrics(this.sessionMetrics, {
-      contextUsed: projection.contextUsage?.used,
-      contextWindow: projection.contextUsage?.size,
-      totalTokens: projection.totalTokenCount,
-      turnCount: projection.turnCount
-    });
+    this.sessionMetrics = mergeProjectionMetrics(
+      this.sessionMetrics,
+      {
+        contextUsed: projection.contextUsage?.used,
+        contextWindow: projection.contextUsage?.size,
+        totalTokens: projection.totalTokenCount,
+        turnCount: projection.turnCount
+      },
+      Boolean(this.options.readSessionUsage)
+    );
     this.updateRuntimeActivity(false);
   }
 
diff --git a/packages/zcode-tui/src/session-status.ts b/packages/zcode-tui/src/session-status.ts
index d6fb2bb..2bfd1b4 100644
--- a/packages/zcode-tui/src/session-status.ts
+++ b/packages/zcode-tui/src/session-status.ts
@@ -53,10 +53,29 @@ export function sessionIdFromUsage(value: unknown): string | undefined {
 }
 
 export function mergeMetrics(current: SessionMetrics, update: SessionMetrics | undefined): SessionMetrics {
-  return update ? { ...current, ...update } : current;
+  if (!update) return current;
+  const defined = Object.fromEntries(
+    Object.entries(update).filter((entry): entry is [string, number] => entry[1] !== undefined)
+  ) as SessionMetrics;
+  return { ...current, ...defined };
 }
 
-export function contextRemainingPercent(metrics: SessionMetrics): number | undefined {
+export function mergeProjectionMetrics(
+  current: SessionMetrics,
+  update: SessionMetrics | undefined,
+  hasAuthoritativeSessionUsage: boolean
+): SessionMetrics {
+  if (!update || !hasAuthoritativeSessionUsage) return mergeMetrics(current, update);
+  const { totalTokens: _projectionTotal, ...contextMetrics } = update;
+  return mergeMetrics(current, contextMetrics);
+}
+
+export function contextUsedPercent(metrics: SessionMetrics): number | undefined {
   if (metrics.contextUsed === undefined || !metrics.contextWindow) return undefined;
-  return Math.max(0, Math.min(100, Math.round((1 - metrics.contextUsed / metrics.contextWindow) * 100)));
+  return Math.max(0, Math.min(100, Math.round(metrics.contextUsed / metrics.contextWindow * 100)));
+}
+
+export function contextRemainingPercent(metrics: SessionMetrics): number | undefined {
+  const used = contextUsedPercent(metrics);
+  return used === undefined ? undefined : 100 - used;
 }
diff --git a/test/session-status.test.ts b/test/session-status.test.ts
index 6e88f9c..93cd009 100644
--- a/test/session-status.test.ts
+++ b/test/session-status.test.ts
@@ -2,7 +2,9 @@ import { describe, expect, test } from "bun:test";
 
 import {
   contextRemainingPercent,
+  contextUsedPercent,
   mergeMetrics,
+  mergeProjectionMetrics,
   projectionMetrics,
   sessionIdFromUsage,
   usageMetrics
@@ -41,6 +43,30 @@ describe("TUI session status", () => {
     expect(contextRemainingPercent({ contextUsed: 200, contextWindow: 100 })).toBe(0);
   });
 
+  test("keeps session-store totals authoritative over runtime projections", () => {
+    const usage = { totalTokens: 18_500, inputTokens: 14_000 };
+    const projection = { totalTokens: 417_202, contextUsed: 32_000, contextWindow: 128_000 };
+
+    expect(mergeProjectionMetrics(usage, projection, true)).toEqual({
+      totalTokens: 18_500,
+      inputTokens: 14_000,
+      contextUsed: 32_000,
+      contextWindow: 128_000
+    });
+    expect(mergeProjectionMetrics({}, projection, false).totalTokens).toBe(417_202);
+  });
+
+  test("does not erase metrics with absent fields and keeps used plus remaining at 100%", () => {
+    expect(mergeMetrics(
+      { totalTokens: 18_500, contextUsed: 32_000 },
+      { contextWindow: 128_000, totalTokens: undefined }
+    )).toEqual({ totalTokens: 18_500, contextUsed: 32_000, contextWindow: 128_000 });
+
+    const metrics = { contextUsed: 1, contextWindow: 8 };
+    expect(contextUsedPercent(metrics)).toBe(13);
+    expect(contextRemainingPercent(metrics)).toBe(87);
+  });
+
   test("extracts the official session identifier from usage snapshots", () => {
     expect(sessionIdFromUsage({ sessionId: "sess_protocol" })).toBe("sess_protocol");
     expect(sessionIdFromUsage({ sessionID: "sess_store" })).toBe("sess_store");