feat(auto-model): route balanced tier to Kimi when images detected (#1604)

## Summary

- Kilo Auto Balanced now supports image inputs by detecting images in
user messages across all three gateway request formats
(`chat_completions`, `responses`, `messages`)
- When the balanced tier would normally route to MiniMax (for `build`,
`explore`, `code` modes or as fallback) and the request contains images,
it overrides to Kimi K2.5 instead, since MiniMax does not support image
inputs
- Sets `supports_images: true` on the balanced auto model so clients
know images are accepted

## Verification

- [x] `pnpm typecheck` passes (exit code 0)
- [x] Pre-push hooks (lint, format, typecheck) pass
- [x] Snapshot test `openrouter-models-sorting.approved.json` updated to
include `image` in balanced model's `input_modalities`

## Visual Changes

N/A

## Reviewer Notes

- The image detection function `requestContainsImages` handles all three
gateway request kinds with their respective image discriminants:
`image_url` (chat_completions), `input_image` (responses), `image`
(Anthropic messages)
- The override only triggers when the resolved model is MiniMax — modes
that already route to Kimi (plan, general, architect, etc.) are
unaffected
- `BALANCED_IMAGE_MODEL` uses reasoning enabled, consistent with all
other Kimi routes in the balanced tier

Author: chrarnoldus

src/lib/kilo-auto-model.ts

@@ -14,6 +14,7 @@ import type {
   OpenRouterChatCompletionRequest,
   OpenRouterReasoningConfig,
 } from '@/lib/providers/openrouter/types';
+import { requestContainsImages } from '@/lib/providers/openrouter/request-helpers';
 import type { ModelSettings, OpenCodeSettings, Verbosity } from '@kilocode/db/schema-types';
 import type OpenAI from 'openai';
 
@@ -104,6 +105,11 @@ const BALANCED_CODE_MODEL: ResolvedAutoModel = {
   model: MINIMAX_CURRENT_MODEL_ID,
 };
 
+const BALANCED_IMAGE_MODEL: ResolvedAutoModel = {
+  model: KIMI_CURRENT_MODEL_ID,
+  reasoning: { enabled: true },
+};
+
 const BALANCED_MODE_TO_MODEL: Record<string, ResolvedAutoModel> = {
   plan: { model: KIMI_CURRENT_MODEL_ID, reasoning: { enabled: true } },
   general: { model: KIMI_CURRENT_MODEL_ID, reasoning: { enabled: true } },
@@ -156,7 +162,7 @@ export const KILO_AUTO_BALANCED_MODEL: AutoModel = {
   max_completion_tokens: 131072,
   prompt_price: '0.0000006',
   completion_price: '0.000003',
-  supports_images: false,
+  supports_images: true,
   roocode_settings: {
     included_tools: ['edit_file'],
     excluded_tools: ['apply_diff'],
@@ -202,7 +208,8 @@ const legacyMapping: Record<string, AutoModel | undefined> = {
 export async function resolveAutoModel(
   model: string,
   modeHeader: string | null,
-  balancePromise: Promise<number>
+  balancePromise: Promise<number>,
+  hasImages: boolean
 ): Promise<ResolvedAutoModel> {
   const mappedModel =
     (Object.hasOwn(legacyMapping, model) ? legacyMapping[model] : null)?.id ?? model;
@@ -216,6 +223,9 @@ export async function resolveAutoModel(
   }
   const mode = modeHeader?.trim().toLowerCase() ?? '';
   if (mappedModel === KILO_AUTO_BALANCED_MODEL.id) {
+    if (hasImages) {
+      return BALANCED_IMAGE_MODEL;
+    }
     return (
       (Object.hasOwn(BALANCED_MODE_TO_MODEL, mode) ? BALANCED_MODE_TO_MODEL[mode] : null) ??
       BALANCED_CODE_MODEL
@@ -234,10 +244,12 @@ export async function applyResolvedAutoModel(
   featureHeader: FeatureValue | null,
   balancePromise: Promise<number>
 ) {
+  const hasImages = requestContainsImages(request);
   const resolved = await resolveAutoModel(
     model,
     featureHeader === 'kiloclaw' ? 'plan' : modeHeader,
-    balancePromise
+    balancePromise,
+    hasImages
   );
   request.body.model = resolved.model;
   if (resolved.reasoning) {

src/lib/models.ts

@@ -48,7 +48,7 @@ export async function getMonitoredModels() {
   const set = new Set<string>();
   for (const model of preferredModels) {
     if (isKiloAutoModel(model)) {
-      set.add((await resolveAutoModel(model, null, Promise.resolve(0))).model);
+      set.add((await resolveAutoModel(model, null, Promise.resolve(0), false)).model);
     } else {
       set.add(model);
     }

src/lib/providers/openrouter/request-helpers.ts

@@ -152,3 +152,44 @@ export function scrubOpenCodeSpecificProperties(request: OpenRouterChatCompletio
   delete body.usage;
   delete body.reasoningEffort;
 }
+
+export function requestContainsImages(request: GatewayRequest): boolean {
+  switch (request.kind) {
+    case 'chat_completions':
+      return request.body.messages.some(
+        msg =>
+          (msg.role === 'user' || msg.role === 'tool') &&
+          Array.isArray(msg.content) &&
+          msg.content.some(part => part.type === 'image_url')
+      );
+    case 'responses': {
+      if (!Array.isArray(request.body.input)) return false;
+      return request.body.input.some(item => {
+        if (typeof item === 'string') return false;
+        if (item.type === 'message') {
+          return (
+            Array.isArray(item.content) && item.content.some(part => part.type === 'input_image')
+          );
+        }
+        if (item.type === 'function_call_output') {
+          return (
+            Array.isArray(item.output) && item.output.some(part => part.type === 'input_image')
+          );
+        }
+        return false;
+      });
+    }
+    case 'messages':
+      return request.body.messages.some(
+        msg =>
+          Array.isArray(msg.content) &&
+          msg.content.some(
+            block =>
+              block.type === 'image' ||
+              (block.type === 'tool_result' &&
+                Array.isArray(block.content) &&
+                block.content.some(inner => inner.type === 'image'))
+          )
+      );
+  }
+}

src/tests/openrouter-models-sorting.approved.json

@@ -50,7 +50,8 @@
       "description": "Great balance of price and capability. Uses Kimi K2.5 for plan, general, architect, orchestrator, ask, debug; MiniMax M2.7 for build, explore, code.",
       "architecture": {
         "input_modalities": [
-          "text"
+          "text",
+          "image"
         ],
         "output_modalities": [
           "text"