feat: auto-compact and auto-clear from the statusLine context size

Both checks compared getTotalTokens() against the threshold. That
counter leaves out cache reads, so it stays far below the real context,
and the 500k cap ruled out thresholds on a 1M window.

POST /api/status-telemetry now hands context_window.total_input_tokens
and context_window_size to Session.noteContextReport(), which runs both
checks. The decision is a pure function, decideAutoThreshold(). The
counter stays the fallback when no report has arrived.

After a /compact or /clear the pre-command report is ignored by value,
since it stays the newest number until the command finishes. The first
differing report came later, so a swallowed command fires again instead
of locking the automation off. A counter summed from JSON usage never
drops after a compact, so it counts from its value at the last one. The
pane parser's counter is absolute and only moves past its high, so a
move clears that baseline and it fires as it did before.

Thresholds go up to the reported window, 1M when unknown, and a higher
value stops at the window. MAX_SESSION_TOKENS follows, and the pane
parser's M-suffix guard checks that cap instead of a fixed 0.5.

Refs #585

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

src/web/public/index.html

@@ -1627,7 +1627,7 @@
                       <span class="set-row-desc">Summarizes the context at the threshold while preserving key information.</span>
                     </div>
                     <div class="set-row-actions">
-                      <input type="number" id="modalAutoCompactThreshold" class="set-num set-num-wide" value="110000" min="10000" max="500000" step="10000" onchange="app.autoSaveAutoCompact()">
+                      <input type="number" id="modalAutoCompactThreshold" class="set-num set-num-wide" value="110000" min="10000" max="1000000" step="10000" onchange="app.autoSaveAutoCompact()">
                       <span class="set-unit">tokens</span>
                       <label class="switch switch-sm"><input type="checkbox" id="modalAutoCompactEnabled" onchange="app.autoSaveAutoCompact()"><span class="slider"></span></label>
                     </div>
@@ -1645,7 +1645,7 @@
                       <span class="set-row-desc">Full context reset at the threshold. Keep it higher than auto-compact.</span>
                     </div>
                     <div class="set-row-actions">
-                      <input type="number" id="modalAutoClearThreshold" class="set-num set-num-wide" value="140000" min="10000" max="500000" step="10000" onchange="app.autoSaveAutoClear()">
+                      <input type="number" id="modalAutoClearThreshold" class="set-num set-num-wide" value="140000" min="10000" max="1000000" step="10000" onchange="app.autoSaveAutoClear()">
                       <span class="set-unit">tokens</span>
                       <label class="switch switch-sm"><input type="checkbox" id="modalAutoClearEnabled" onchange="app.autoSaveAutoClear()"><span class="slider"></span></label>
                     </div>

src/web/public/session-ui.js

@@ -2814,7 +2814,11 @@ Object.assign(CodemanApp.prototype, {
     // Populate respawn config from saved state
     this.loadSavedRespawnConfig(sessionId);
 
-    // Populate auto-compact/clear from session state
+    // Populate auto-compact/clear from session state. A threshold above the model's window
+    // can never fire, so the inputs stop there once the statusline has reported it.
+    const maxThreshold = session.contextWindowSize ?? 1000000;
+    document.getElementById('modalAutoCompactThreshold').max = maxThreshold;
+    document.getElementById('modalAutoClearThreshold').max = maxThreshold;
     document.getElementById('modalAutoCompactEnabled').checked = session.autoCompactEnabled ?? false;
     document.getElementById('modalAutoCompactThreshold').value = session.autoCompactThreshold ?? 110000;
     document.getElementById('modalAutoCompactPrompt').value = session.autoCompactPrompt ?? '';

src/web/routes/status-telemetry-routes.ts

@@ -65,6 +65,13 @@ export function registerStatusTelemetryRoutes(app: FastifyInstance, ctx: Session
       session.noteReportedModel('statusline', payload?.model?.display_name);
     }
 
+    // The context size drives auto-compact and auto-clear. A render without one (the exporter
+    // can post before the first API response) keeps the last report instead of wiping it.
+    const status = reportsStatusLine ? parseSessionStatus(payload) : null;
+    if (session && status?.inputTokens !== undefined) {
+      session.noteContextReport({ tokens: status.inputTokens, windowSize: status.contextWindowSize });
+    }
+
     // Prompt-cache state of the main conversation (Claude Code v2.1.251+): kept on the
     // session for the Session Options readout and `toState()`, broadcast only when the
     // report changes (the statusline fires on every assistant message). The broadcast

src/web/schemas.ts

@@ -733,6 +733,7 @@ export const StatusTelemetrySchema = z.object({
           used_percentage: z.number().nullish(),
           total_input_tokens: z.number().nullish(),
           total_output_tokens: z.number().nullish(),
+          context_window_size: z.number().nullish(),
         })
         .nullish(),
       cost: z.object({ total_cost_usd: z.number().nullish() }).nullish(),