diff --git a/src/shared/constants/visionBridgeDefaults.ts b/src/shared/constants/visionBridgeDefaults.ts
index 21050b0c6e..869e4dee8f 100644
--- a/src/shared/constants/visionBridgeDefaults.ts
+++ b/src/shared/constants/visionBridgeDefaults.ts
@@ -17,6 +17,11 @@ const FORCED_VISION_BRIDGE_MODELS = new Set<string>([
   "opencode-go/qwen3.5-plus",
   "opencode-zen/deepseek-v4-flash",
   "opencode-zen/deepseek-v4-pro",
+  // tokenrouter provider: upstream models overstate vision support.
+  // Force Vision Bridge so images are routed through the configured
+  // vision model instead of being passed through to text-only backends.
+  "tokenrouter/deepseek-v4-pro",
+  "tokenrouter/deepseek-v4-flash",
 ]);
 
 export function isVisionBridgeForcedModel(model: string | null | undefined): boolean {
diff --git a/tests/unit/visionBridgeDefaults.test.ts b/tests/unit/visionBridgeDefaults.test.ts
index 65042c8eb9..690da33c0d 100644
--- a/tests/unit/visionBridgeDefaults.test.ts
+++ b/tests/unit/visionBridgeDefaults.test.ts
@@ -39,6 +39,14 @@ test("isVisionBridgeForcedModel does not blanket-force GPT-family models", () =>
   assert.strictEqual(isVisionBridgeForcedModel("openai/gpt-4o-mini"), false);
 });
 
+test("isVisionBridgeForcedModel forces tokenrouter deepseek models (text-only backend, #3946)", () => {
+  // These route through a Fireworks text-only backend that overstates vision
+  // support at the provider level, so they must be force-bridged or raw image
+  // data leaks to a backend that cannot process it.
+  assert.strictEqual(isVisionBridgeForcedModel("tokenrouter/deepseek-v4-pro"), true);
+  assert.strictEqual(isVisionBridgeForcedModel("tokenrouter/deepseek-v4-flash"), true);
+});
+
 test("getVisionBridgeConfig returns defaults when no settings provided", () => {
   const config = getVisionBridgeConfig({});