refactor(core): centralize context-window constant (contextWindowFor)

apps/cli/src/commands.ts

@@ -9,7 +9,7 @@ import type {
   SessionMeta,
   StoredMessage,
 } from '@deepcode/core';
-import { redact, type Credentials } from '@deepcode/core';
+import { contextWindowFor, redact, type Credentials } from '@deepcode/core';
 
 export interface SessionContext {
   cwd: string;
@@ -220,7 +220,7 @@ export const ContextCommand: SlashCommand = {
   description: 'Show context window usage.',
   run(_args, ctx) {
     const used = ctx.usage.inputTokens + ctx.usage.outputTokens;
-    const ctxMax = 128_000;
+    const ctxMax = contextWindowFor(ctx.model);
     const pct = ((used / ctxMax) * 100).toFixed(1);
     return [
       `Context: ${used.toLocaleString()} / ${ctxMax.toLocaleString()} (${pct}%)`,

apps/cli/src/headless.ts

@@ -29,6 +29,7 @@ import {
   buildSkillsDescriptionBlock,
   closeAllMcpServers,
   connectAllMcpServers,
+  contextWindowFor,
   findStyle,
   loadMemory,
   loadOutputStyles,
@@ -239,7 +240,7 @@ export async function runHeadless(opts: HeadlessOpts): Promise<number> {
       mode,
       permissions: settings.permissions,
       hooks,
-      autoCompact: { contextWindow: 128_000, threshold: 0.8 },
+      autoCompact: { contextWindow: contextWindowFor(model), threshold: 0.8 },
       autoMode: settings.autoMode,
       sandboxConfig: settings.sandbox,
       // In headless mode there's no human to ask: auto-deny anything that

apps/cli/src/repl.ts

@@ -22,6 +22,7 @@ import {
   loadOutputStyles,
   loadSettings,
   loadSkills,
+  contextWindowFor,
   makeSkillTool,
   resolveCredentials,
   runAgent,
@@ -308,7 +309,7 @@ export async function startRepl(opts: ReplOpts): Promise<number> {
       mode: ctx.mode as Mode,
       permissions: settings.permissions,
       hooks,
-      autoCompact: { contextWindow: 128_000, threshold: 0.8 },
+      autoCompact: { contextWindow: contextWindowFor(ctx.model), threshold: 0.8 },
       autoMode: settings.autoMode,
       sandboxConfig: settings.sandbox,
       approval: async (toolName, _input, verdict) => {

apps/desktop/src/screens/Repl.tsx

@@ -24,6 +24,7 @@ import {
   type KeyBinding,
   type VimMode,
 } from '@deepcode/core/dist/keybindings/vim.js';
+import { contextWindowFor } from '@deepcode/core/dist/providers/deepseek.js';
 import { Dropdown, type DropdownOption } from '../components/Dropdown.js';
 import { Pill } from '../components/Pill.js';
 import { PlusMenu } from '../components/PlusMenu.js';
@@ -476,7 +477,7 @@ export function ReplScreen({ projectPath, onTurnComplete }: ReplScreenProps): JS
   const activeAssistantIdx = lastAssistantIndex(messages);
 
   // ── Context bar fill ──
-  const contextWindow = 128_000;
+  const contextWindow = contextWindowFor(model);
   const usedTokens = usage.inputTokens + usage.outputTokens;
   const fillPct = Math.min(100, (usedTokens / contextWindow) * 100);
 

packages/core/src/index.ts

@@ -12,7 +12,9 @@ export type * from './types.js';
 export {
   DeepSeekProvider,
   DEEPSEEK_MODELS,
+  DEFAULT_CONTEXT_WINDOW,
   EFFORT_PARAMS,
+  contextWindowFor,
   type DeepSeekProviderOpts,
   type Provider,
   type ProviderResult,

packages/core/src/providers/deepseek.ts

@@ -25,6 +25,19 @@ export const DEEPSEEK_MODELS: Record<DeepSeekModel, { ctx: number; maxOutput: nu
   'deepseek-v4-pro': { ctx: 128_000, maxOutput: 8_192 },
 };
 
+/** Fallback context window for an unrecognized model id. */
+export const DEFAULT_CONTEXT_WINDOW = 128_000;
+
+/**
+ * Context-window size (tokens) for a model id. Single source of truth for the
+ * context-bar + auto-compact threshold across CLI and desktop — avoids the
+ * 128_000 literal drifting out of sync with DEEPSEEK_MODELS. Falls back to
+ * DEFAULT_CONTEXT_WINDOW for unknown (e.g. user-typed) model ids.
+ */
+export function contextWindowFor(model: string): number {
+  return DEEPSEEK_MODELS[model as DeepSeekModel]?.ctx ?? DEFAULT_CONTEXT_WINDOW;
+}
+
 /**
  * Effort → DeepSeek API parameters.
  * Numbers from docs/design/effort-levels.md §3.2.

packages/core/src/providers/index.ts

@@ -8,5 +8,11 @@ export type {
   ProviderUsage,
   ProviderStreamHandlers,
 } from './types.js';
-export { DeepSeekProvider, DEEPSEEK_MODELS, EFFORT_PARAMS } from './deepseek.js';
+export {
+  DeepSeekProvider,
+  DEEPSEEK_MODELS,
+  DEFAULT_CONTEXT_WINDOW,
+  EFFORT_PARAMS,
+  contextWindowFor,
+} from './deepseek.js';
 export type { DeepSeekProviderOpts } from './deepseek.js';