[v3.8.50] feat(combo): add maxContextWindow to contextRequirements (fixes #8777) (#8790)

Validated in local merge-train T6 (ungrouped batch 1)

open-sse/services/combo/contextRequirements.ts

@@ -9,6 +9,7 @@ import type { ComboLogger, ResolvedComboTarget } from "./types.ts";
 
 export interface ContextRequirements {
   minContextWindow?: number;
+  maxContextWindow?: number;
   preferLargeContext?: boolean;
   contextFilterMode?: "strict" | "lenient";
 }
@@ -51,10 +52,15 @@ export function applyContextRequirements(
 ): ResolvedComboTarget[] {
   if (!requirements || targets.length === 0) return targets;
 
-  const { minContextWindow, preferLargeContext, contextFilterMode = "lenient" } = requirements;
+  const {
+    minContextWindow,
+    maxContextWindow,
+    preferLargeContext,
+    contextFilterMode = "lenient",
+  } = requirements;
 
   // No requirements specified
-  if (!minContextWindow && !preferLargeContext) return targets;
+  if (!minContextWindow && !maxContextWindow && !preferLargeContext) return targets;
 
   let filtered = targets;
 
@@ -108,6 +114,34 @@ export function applyContextRequirements(
     }
   }
 
+  // Apply maxContextWindow filtering
+  if (maxContextWindow && maxContextWindow > 0) {
+    const beforeFilterCount = filtered.length;
+
+    filtered = filtered.filter((target) => {
+      const contextWindow = getTargetContextWindow(target);
+
+      // Unknown context limit handling
+      if (contextWindow === null) {
+        return contextFilterMode === "lenient";
+      }
+
+      // Known context limit - check threshold
+      return contextWindow <= maxContextWindow;
+    });
+
+    if (filtered.length < beforeFilterCount) {
+      log.info(
+        "COMBO",
+        `Context requirements: filtered ${beforeFilterCount} → ${filtered.length} targets (maxContextWindow: ${maxContextWindow}, mode: ${contextFilterMode})`
+      );
+      log.debug?.(
+        "COMBO",
+        `Context requirements: kept models ${filtered.map((t) => t.modelStr).join(", ")}`
+      );
+    }
+  }
+
   // Apply preferLargeContext sorting
   if (preferLargeContext && filtered.length > 1) {
     filtered = [...filtered].sort((a, b) => {

open-sse/services/comboConfig.ts

@@ -179,6 +179,7 @@ const DEFAULT_COMBO_CONFIG = {
   contextRequirements: undefined as
     | {
         minContextWindow?: number;
+        maxContextWindow?: number;
         preferLargeContext?: boolean;
         contextFilterMode?: "strict" | "lenient";
       }

src/shared/validation/schemas/combo.ts

@@ -239,11 +239,13 @@ export const comboRuntimeConfigSchema = z
       .optional(),
     // Context window requirements for combo target filtering and sorting.
     // minContextWindow: filters out models with context windows below this threshold.
+    // maxContextWindow: filters out models with context windows above this threshold.
     // preferLargeContext: sorts remaining targets by context size (descending).
     // contextFilterMode: "strict" excludes unknown-context models, "lenient" includes them.
     contextRequirements: z
       .object({
         minContextWindow: z.coerce.number().int().min(0).max(10_000_000).optional(),
+        maxContextWindow: z.coerce.number().int().min(0).max(10_000_000).optional(),
         preferLargeContext: z.boolean().optional(),
         contextFilterMode: z.enum(["strict", "lenient"]).optional(),
       })

tests/unit/combo-context-requirements.test.ts

@@ -7,11 +7,13 @@ import { comboRuntimeConfigSchema } from "@/shared/validation/schemas/combo";
 // production schema changes shape.
 describe("Combo Context Requirements", () => {
   describe("Schema Validation", () => {
-    it("should accept valid minContextWindow", () => {
+    it("should accept valid minContextWindow and maxContextWindow", () => {
       const schema = comboRuntimeConfigSchema;
 
       const valid = [
         { contextRequirements: { minContextWindow: 8192 } },
+        { contextRequirements: { maxContextWindow: 32000 } },
+        { contextRequirements: { minContextWindow: 8192, maxContextWindow: 128000 } },
         { contextRequirements: { minContextWindow: 32000 } },
         { contextRequirements: { minContextWindow: 128000 } },
         { contextRequirements: { minContextWindow: 1000000 } },
@@ -25,13 +27,16 @@ describe("Combo Context Requirements", () => {
       }
     });
 
-    it("should reject invalid minContextWindow", () => {
+    it("should reject invalid minContextWindow or maxContextWindow", () => {
       const schema = comboRuntimeConfigSchema;
 
       const invalid = [
         { contextRequirements: { minContextWindow: -1 } },
         { contextRequirements: { minContextWindow: 20_000_000 } },
         { contextRequirements: { minContextWindow: "invalid" } },
+        { contextRequirements: { maxContextWindow: -1 } },
+        { contextRequirements: { maxContextWindow: 20_000_000 } },
+        { contextRequirements: { maxContextWindow: "invalid" } },
       ];
 
       for (const input of invalid) {

tests/unit/combo-target-resolution-split.test.ts

@@ -146,3 +146,43 @@ test("request exceeding every known context window returns a 400 earlyResponse",
   assert.equal(body.diagnostics?.terminalReason, "context_length_exceeded");
   assert.equal(body.diagnostics?.attempted, 0);
 });
+
+// #8790: maxContextWindow rejects every target whose known context window
+// exceeds the configured ceiling. When that empties the pool, the
+// context-requirements guard (applyContinuityFilters → #8786's
+// buildEmptyComboTargetsPayload) must surface a 404 context_requirements_exhausted
+// early response instead of letting an empty orderedTargets[] fall through to the
+// attempt loop.
+test("maxContextWindow rejecting every target returns a 404 context_requirements_exhausted earlyResponse", async () => {
+  saveModelsDevCapabilities({
+    "unit-target-resolution-max": {
+      big1: capabilityEntry(500_000),
+      big2: capabilityEntry(1_000_000),
+    },
+  });
+
+  const result = await resolveComboTargetPipeline(
+    deps({
+      combo: {
+        id: "c3",
+        name: "max-context-window-exhausted",
+        models: ["unit-target-resolution-max/big1", "unit-target-resolution-max/big2"],
+        config: {},
+      },
+      config: {
+        contextRequirements: { maxContextWindow: 128_000, contextFilterMode: "strict" },
+      },
+    })
+  );
+
+  assert.ok("earlyResponse" in result, "expected a context-requirements-exhausted early response");
+  if (!("earlyResponse" in result)) return;
+  assert.equal(result.earlyResponse.status, 404);
+  const body = (await result.earlyResponse.json()) as {
+    error?: { code?: string };
+    diagnostics?: { terminalReason?: string; excluded?: unknown[] };
+  };
+  assert.equal(body.error?.code, "model_not_found");
+  assert.equal(body.diagnostics?.terminalReason, "context_requirements_exhausted");
+  assert.equal(body.diagnostics?.excluded?.length, 2);
+});

tests/unit/combo/context-requirements-integration.test.ts

@@ -65,6 +65,29 @@ describe("Context Requirements Integration", () => {
     assert.equal(result.length, 0);
   });
 
+  it("should filter targets above maxContextWindow in strict mode", () => {
+    const targets = [
+      { modelStr: "claude-opus-4-5", provider: "anthropic", weight: 1 }, // 200k
+      { modelStr: "claude-sonnet-4-5", provider: "anthropic", weight: 1 }, // 200k
+      { modelStr: "claude-sonnet-4-6", provider: "anthropic", weight: 1 }, // 1000k (1M)
+      { modelStr: "claude-opus-4-6", provider: "anthropic", weight: 1 }, // 1000k (1M)
+    ];
+
+    const requirements = {
+      maxContextWindow: 500000,
+      contextFilterMode: "strict" as const,
+    };
+
+    const result = applyContextRequirements(targets, requirements, mockLog);
+    assert.equal(result.length, 2);
+    assert.ok(
+      result.every(
+        (target) => target.modelStr === "claude-opus-4-5" || target.modelStr === "claude-sonnet-4-5"
+      ),
+      "Should only include targets with context window <= 500000"
+    );
+  });
+
   it("should handle lenient mode with unknown context models", () => {
     const targets = [
       { modelStr: "gpt-4o", provider: "openai", weight: 1 },