feat(statusline): add built-in context provider showing context window usage (#234)

packages/cli/src/tests/context-provider.test.ts

@@ -0,0 +1,34 @@
+import { test } from "node:test";
+import assert from "node:assert/strict";
+import { createContextStatusProvider } from "../ui/statusline/context-provider";
+
+test("context statusline provider reports context usage percentage (#234)", async () => {
+  const provider = createContextStatusProvider("ctx", undefined, false, undefined);
+  const text = await provider.fetch({
+    projectRoot: "/tmp",
+    signal: new AbortController().signal,
+    getSessionInfo: () => ({
+      activeSessionId: "s1",
+      messageCount: 10,
+      requestCount: 2,
+      totalTokens: 100000,
+      activeTokens: 131072,
+      maxContextTokens: 1024 * 1024,
+      model: "deepseek-v4-flash",
+      thinkingEnabled: false,
+      reasoningEffort: "high",
+      toolUsage: {},
+    }),
+  });
+  assert.equal(text, "ctx 13%");
+});
+
+test("context statusline provider returns empty without an active session (#234)", async () => {
+  const provider = createContextStatusProvider("ctx");
+  const text = await provider.fetch({
+    projectRoot: "/tmp",
+    signal: new AbortController().signal,
+    getSessionInfo: () => null,
+  });
+  assert.equal(text, "");
+});

packages/cli/src/ui/statusline/context-provider.ts

@@ -0,0 +1,27 @@
+import type { StatusProvider } from "./types";
+
+/**
+ * Built-in statusline provider that shows the current session's context-window
+ * usage as a percentage, e.g. `ctx 12%`. (#234)
+ */
+export function createContextStatusProvider(
+  id: string,
+  color?: string,
+  newLine?: boolean,
+  maxLength?: number
+): StatusProvider {
+  return {
+    id,
+    color,
+    newLine,
+    maxLength,
+    fetch: async (ctx) => {
+      const info = ctx.getSessionInfo?.();
+      if (!info || !info.activeSessionId || info.maxContextTokens <= 0) {
+        return "";
+      }
+      const percent = Math.min(100, Math.round((info.activeTokens / info.maxContextTokens) * 100));
+      return `ctx ${percent}%`;
+    },
+  };
+}

packages/cli/src/ui/statusline/manager.ts

@@ -1,6 +1,7 @@
 import type { ResolvedStatusLineSettings, StatusLineProviderConfig } from "@vegamo/deepcode-core";
 import { sanitizeStatusText } from "./sanitize";
 import { createCommandStatusProvider } from "./command-provider";
+import { createContextStatusProvider } from "./context-provider";
 import { loadModuleProvider, validateModulePath } from "./module-provider";
 import type { SessionInfo, StatusProvider, StatusSegment } from "./types";
 
@@ -147,6 +148,9 @@ export class StatusLineManager {
       }
       return provider;
     }
+    if (config.type === "context") {
+      return createContextStatusProvider(providerId, config.color, config.newLine, config.maxLength);
+    }
     return null;
   }
 

packages/core/src/settings.ts

@@ -64,6 +64,13 @@ export type StatusLineProviderConfig =
       color?: string;
       newLine?: boolean;
       maxLength?: number;
+    }
+  | {
+      type: "context";
+      id?: string;
+      color?: string;
+      newLine?: boolean;
+      maxLength?: number;
     };
 
 export type StatusLineSettings = {
@@ -357,6 +364,15 @@ function normalizeStatusLineProvider(value: unknown): StatusLineProviderConfig |
       maxLength,
     };
   }
+  if (type === "context") {
+    return {
+      type: "context",
+      id,
+      color,
+      newLine,
+      maxLength,
+    };
+  }
   return null;
 }
 

packages/core/src/tests/settings-and-notify.test.ts

@@ -11,6 +11,20 @@ import { applyModelConfigSelection, resolveSettings, resolveSettingsSources } fr
 
 const TEST_PROCESS_ENV = {};
 
+test("resolveSettingsSources normalizes the statusline context provider (#234)", () => {
+  const resolved = resolveSettingsSources(
+    {
+      statusline: { enabled: true, providers: [{ type: "context" }] },
+      env: { API_KEY: "sk-test" },
+    },
+    null,
+    { model: "default-model", baseURL: "https://default.example.com" },
+    TEST_PROCESS_ENV
+  );
+  assert.equal(resolved.statusline.providers.length, 1);
+  assert.equal(resolved.statusline.providers[0]?.type, "context");
+});
+
 test("resolveSettings reads top-level thinkingEnabled, notify, and webSearchTool", () => {
   const resolved = resolveSettings(
     {