diff --git a/docs/ops/VM_DEPLOYMENT_GUIDE.md b/docs/ops/VM_DEPLOYMENT_GUIDE.md
index 69e3ac4209..c0e64c74e7 100644
--- a/docs/ops/VM_DEPLOYMENT_GUIDE.md
+++ b/docs/ops/VM_DEPLOYMENT_GUIDE.md
@@ -429,5 +429,7 @@ For deployments on small VPS instances (1 GB RAM or less):
 
 - **Disable background services** — set `OMNIROUTE_DISABLE_BACKGROUND_SERVICES=1` to skip scheduler, MCP server, and periodic maintenance tasks. See `docs/reference/ENVIRONMENT.md`.
 - **Use SQLite WAL mode** — enabled by default, reduces peak memory during concurrent reads.
+- **Cap the V8 heap** — set `OMNIROUTE_MEMORY_MB` (e.g. `512`) so the runtime does not calibrate a ceiling larger than the VM. See `docs/reference/ENVIRONMENT.md`.
+- **Limit concurrent heavy requests** — lower `OMNIROUTE_CHAT_MAX_HEAVY_IN_FLIGHT` (default `1`); excess requests get a retryable `503` with `Retry-After` instead of competing for memory.
 - **Avoid `next build` on the VPS** — build locally and deploy the standalone output (`.next/standalone/`).
 - **Monitor with `top` / `free -m`** — OmniRoute typically uses 200-400 MB RSS at idle on a 1 GB VM.
diff --git a/open-sse/services/combo/comboStructure.ts b/open-sse/services/combo/comboStructure.ts
index 76ef372dc2..0430f03482 100644
--- a/open-sse/services/combo/comboStructure.ts
+++ b/open-sse/services/combo/comboStructure.ts
@@ -18,6 +18,7 @@ import { getHiddenModelsByProvider } from "../../../src/lib/db/models";
 import { getComboModelString, normalizeComboStep } from "../../../src/lib/combos/steps.ts";
 import { getProviderByAlias, getProviderById } from "../../../src/shared/constants/providers.ts";
 import { estimateTokens } from "../contextManager.ts";
+import { containsMediaKind } from "../../utils/mediaParts.ts";
 import { getResolvedModelCapabilities } from "../modelCapabilities.ts";
 import { parseModel, stripContextWindowSuffix } from "../model.ts";
 import { dedupeTargetsByExecutionKey, isRecord } from "./comboData.ts";
@@ -481,21 +482,8 @@ function estimateRequestInputTokens(body: Record<string, unknown>): number {
   return Object.keys(estimatePayload).length > 0 ? estimateTokens(estimatePayload) : 0;
 }
 
-function valueContainsImagePart(value: unknown, depth = 0): boolean {
-  if (depth > 8 || value === null || value === undefined) return false;
-  if (typeof value === "string") return value.startsWith("data:image/");
-  if (Array.isArray(value)) return value.some((entry) => valueContainsImagePart(entry, depth + 1));
-  if (!isRecord(value)) return false;
-
-  const type = typeof value.type === "string" ? value.type.toLowerCase() : null;
-  if (type === "image" || type === "image_url" || type === "input_image") return true;
-  if ("image_url" in value || "input_image" in value) return true;
-
-  const source = isRecord(value.source) ? value.source : null;
-  const mediaType = typeof source?.media_type === "string" ? source.media_type.toLowerCase() : "";
-  if (mediaType.startsWith("image/")) return true;
-
-  return Object.values(value).some((entry) => valueContainsImagePart(entry, depth + 1));
+function valueContainsImagePart(value: unknown): boolean {
+  return containsMediaKind([{ content: [value] }], "image");
 }
 
 export function deriveRequestCompatibilityRequirements(
@@ -533,6 +521,8 @@ function hasKnownCompatibleContextLimit(
   return evaluateContextLimit(capabilities, requirements, target.modelStr) === true;
 }
 
+const HARD_COMPAT_REASONS = new Set(["tools", "vision", "structured_output", "output_tokens"]);
+
 /**
  * #8332: vision is a hard requirement, not a soft preference — a target whose vision
  * support is not confirmed can never succeed on an image_url request. Callers
@@ -616,7 +606,7 @@ export type CompatFilterOptions = {
   failOpen?: boolean;
 };
 
-function hasHardCapabilityFailure(reasons: string[]): boolean {
+export function hasHardCapabilityFailure(reasons: string[]): boolean {
   return reasons.some((reason) => HARD_COMPAT_REASONS.has(reason));
 }
 
diff --git a/tests/unit/combo-vision-aware-routing.test.ts b/tests/unit/combo-vision-aware-routing.test.ts
index ae84b3ce08..8d5c186c3f 100644
--- a/tests/unit/combo-vision-aware-routing.test.ts
+++ b/tests/unit/combo-vision-aware-routing.test.ts
@@ -37,6 +37,8 @@ process.env.DATA_DIR = TEST_DATA_DIR;
 const core = await import("../../src/lib/db/core.ts");
 const { getResolvedModelCapabilities } = await import("../../src/lib/modelCapabilities.ts");
 const { filterTargetsByRequestCompatibility } = await import("../../open-sse/services/combo.ts");
+const { deriveRequestCompatibilityRequirements, hasHardCapabilityFailure } =
+  await import("../../open-sse/services/combo/comboStructure.ts");
 
 test.after(() => {
   core.resetDbInstance();
@@ -100,6 +102,28 @@ test("image request: combo drops the non-vision target, keeps the vision target"
   assert.ok(!ids.includes("mistral/ministral-14b-latest"), "non-vision target must be dropped");
 });
 
+test("nested case-insensitive image indicators still enforce hard vision compatibility", () => {
+  const requirements = deriveRequestCompatibilityRequirements({
+    messages: [
+      {
+        role: "user",
+        content: [
+          {
+            payload: {
+              type: "IMAGE_URL",
+              image_url: { url: "data:image/png;base64,iVBOR" },
+            },
+          },
+        ],
+      },
+    ],
+  });
+
+  assert.equal(requirements.requiresVision, true);
+  assert.equal(hasHardCapabilityFailure(["vision"]), true);
+  assert.equal(hasHardCapabilityFailure(["context_window"]), false);
+});
+
 test(
   "image request with NO confirmed-vision target: strip all (#8332 — never dispatch " +
     "an image body to a confirmed-non-vision target, even as a last resort)",