feat: Make Sonnet 4.6 free for one week in review mode

src/app/api/openrouter/[...path]/route.ts

@@ -14,6 +14,8 @@ import {
   isDataCollectionRequiredOnKiloCodeOnly,
   isDeadFreeModel,
   isSlackbotOnlyModel,
+  isReviewOnlyModel,
+  isReviewPromotionActive,
   isRateLimitedModel,
 } from '@/lib/models';
 import {
@@ -250,6 +252,14 @@ export async function POST(request: NextRequest): Promise<NextResponseType<unkno
     return modelDoesNotExistResponse();
   }
 
+  // Review-only promotional models are only available through Code Reviewer (internalApiUse)
+  // and only during the active promotion window
+  if (isReviewOnlyModel(originalModelIdLowerCased)) {
+    if (!internalApiUse || !isReviewPromotionActive(originalModelIdLowerCased)) {
+      return modelDoesNotExistResponse();
+    }
+  }
+
   // Extract properties for usage context
   const tokenEstimates = estimateChatTokens(requestBodyParsed);
   const promptInfo = extractPromptInfo(requestBodyParsed);

src/lib/code-reviews/core/constants.ts

@@ -4,15 +4,29 @@
  * Constants used throughout the code review system.
  */
 
+import { getActiveReviewPromotionModel } from '@/lib/models';
+
 // ============================================================================
 // Review Configuration
 // ============================================================================
 
 /**
- * Default model for code reviews
- * Using Claude Sonnet 4.5 as specified in the plan
+ * Default model for code reviews.
+ * Falls back to Claude Sonnet 4.5 when no promotion is active.
  */
-export const DEFAULT_CODE_REVIEW_MODEL = 'anthropic/claude-sonnet-4.5';
+const BASE_CODE_REVIEW_MODEL = 'anthropic/claude-sonnet-4.5';
+
+/**
+ * Returns the effective default model for code reviews.
+ * If a review-only promotional model is currently active, it takes precedence.
+ */
+export function getDefaultCodeReviewModel(): string {
+  const promoModel = getActiveReviewPromotionModel();
+  return promoModel?.internal_id ?? BASE_CODE_REVIEW_MODEL;
+}
+
+/** @deprecated Use getDefaultCodeReviewModel() for promotion-aware model selection */
+export const DEFAULT_CODE_REVIEW_MODEL = BASE_CODE_REVIEW_MODEL;
 
 /**
  * Default mode for cloud agent sessions

src/lib/code-reviews/triggers/prepare-review-payload.ts

@@ -37,7 +37,8 @@ import type {
 } from '../prompts/generate-prompt';
 import { getIntegrationById } from '@/lib/integrations/db/platform-integrations';
 import { getCodeReviewById } from '../db/code-reviews';
-import { DEFAULT_CODE_REVIEW_MODEL, DEFAULT_CODE_REVIEW_MODE } from '../core/constants';
+import { DEFAULT_CODE_REVIEW_MODE, getDefaultCodeReviewModel } from '../core/constants';
+import { getActiveReviewPromotionModel } from '@/lib/models';
 import type { Owner } from '../core';
 import { generateReviewPrompt } from '../prompts/generate-prompt';
 import type { CodeReviewAgentConfig } from '@/lib/agent-config/core/types';
@@ -341,7 +342,7 @@ export async function prepareReviewPayload(
             kilocodeOrganizationId: owner.type === 'org' ? owner.id : undefined,
             prompt,
             mode: DEFAULT_CODE_REVIEW_MODE as 'code',
-            model: config.model_slug || DEFAULT_CODE_REVIEW_MODEL,
+            model: config.model_slug || getDefaultCodeReviewModel(),
             upstreamBranch: review.head_ref,
           }
         : {
@@ -351,7 +352,7 @@ export async function prepareReviewPayload(
             kilocodeOrganizationId: owner.type === 'org' ? owner.id : undefined,
             prompt,
             mode: DEFAULT_CODE_REVIEW_MODE as 'code',
-            model: config.model_slug || DEFAULT_CODE_REVIEW_MODEL,
+            model: config.model_slug || getDefaultCodeReviewModel(),
             upstreamBranch: review.head_ref,
           };
 
@@ -365,6 +366,21 @@ export async function prepareReviewPayload(
       });
     }
 
+    // 6b. Log if a promotional model is being used for tracking
+    const activePromoModel = getActiveReviewPromotionModel();
+    const effectiveModel = sessionInput.model;
+    if (activePromoModel && effectiveModel === activePromoModel.internal_id) {
+      logExceptInTest('[prepareReviewPayload] Using promotional model for code review', {
+        reviewId,
+        promotionModel: activePromoModel.public_id,
+        effectiveModel,
+        promotionStart: activePromoModel.promotion_start,
+        promotionEnd: activePromoModel.promotion_end,
+        ownerType: owner.type,
+        ownerId: owner.id,
+      });
+    }
+
     // 7. Build complete payload
     const payload: CodeReviewPayload = {
       reviewId,

src/lib/models.ts

@@ -7,6 +7,7 @@ import {
   CLAUDE_OPUS_CURRENT_MODEL_ID,
   CLAUDE_SONNET_CURRENT_MODEL_ID,
   opus_46_free_slackbot_model,
+  sonnet_46_free_review_model,
 } from '@/lib/providers/anthropic';
 import { corethink_free_model } from '@/lib/providers/corethink';
 import { giga_potato_model } from '@/lib/providers/gigapotato';
@@ -65,6 +66,7 @@ export const kiloFreeModels = [
   minimax_m21_free_model,
   minimax_m25_free_model,
   opus_46_free_slackbot_model,
+  sonnet_46_free_review_model,
   grok_code_fast_1_optimized_free_model,
   zai_glm47_free_model,
   zai_glm5_free_model,
@@ -96,3 +98,41 @@ export function isDeadFreeModel(model: string): boolean {
 export function isSlackbotOnlyModel(model: string): boolean {
   return !!kiloFreeModels.find(m => m.public_id === model && m.slackbot_only);
 }
+
+/**
+ * Check if a model is a review-only promotional model.
+ * These models are hidden from the public model list and only available in Code Reviewer.
+ */
+export function isReviewOnlyModel(model: string): boolean {
+  return !!kiloFreeModels.find(m => m.public_id === model && m.review_only);
+}
+
+/**
+ * Check if a review-only promotional model is currently within its active promotion window.
+ * Returns false for non-review-only models or if the promotion has expired.
+ */
+export function isReviewPromotionActive(model: string, now = new Date()): boolean {
+  const freeModel = kiloFreeModels.find(
+    m => m.public_id === model && m.review_only && m.is_enabled
+  );
+  if (!freeModel) return false;
+  if (freeModel.promotion_start && now < new Date(freeModel.promotion_start)) return false;
+  if (freeModel.promotion_end && now >= new Date(freeModel.promotion_end)) return false;
+  return true;
+}
+
+/**
+ * Get the active review promotion model, if any.
+ * Returns the model config if a review-only promotion is currently active, null otherwise.
+ */
+export function getActiveReviewPromotionModel(now = new Date()): KiloFreeModel | null {
+  return (
+    kiloFreeModels.find(
+      m =>
+        m.review_only &&
+        m.is_enabled &&
+        (!m.promotion_start || now >= new Date(m.promotion_start)) &&
+        (!m.promotion_end || now < new Date(m.promotion_end))
+    ) ?? null
+  );
+}

src/lib/providers/anthropic.ts

@@ -21,6 +21,24 @@ export const opus_46_free_slackbot_model = {
   slackbot_only: true,
 } as KiloFreeModel;
 
+export const SONNET_46_REVIEW_PROMO_MODEL_ID = 'anthropic/claude-sonnet-4-6-20250514:review';
+
+export const sonnet_46_free_review_model = {
+  public_id: SONNET_46_REVIEW_PROMO_MODEL_ID,
+  display_name: 'Anthropic: Claude Sonnet 4.6 (Free for Code Reviewer)',
+  description: 'Claude Sonnet 4.6 — free for one week in Code Reviewer (review mode)',
+  context_length: 200_000,
+  max_completion_tokens: 16384,
+  is_enabled: true,
+  flags: ['reasoning', 'prompt_cache', 'vision'],
+  gateway: 'openrouter',
+  internal_id: 'anthropic/claude-sonnet-4-6-20250514',
+  inference_providers: ['anthropic'],
+  review_only: true,
+  promotion_start: '2026-02-18T00:00:00Z',
+  promotion_end: '2026-02-25T00:00:00Z',
+} as KiloFreeModel;
+
 const ENABLE_ANTHROPIC_STRICT_TOOL_USE = false;
 
 const ENABLE_ANTHROPIC_AUTOMATIC_CACHING = true;

src/lib/providers/kilo-free-model.ts

@@ -16,6 +16,12 @@ export type KiloFreeModel = {
   inference_providers: OpenRouterInferenceProviderId[];
   /** If true, this model is only available through Kilo for Slack (internalApiUse) and hidden from public model list */
   slackbot_only?: boolean;
+  /** If true, this model is only available in Code Reviewer (review mode) and hidden from the public model list */
+  review_only?: boolean;
+  /** Promotion start date (ISO 8601). If set, the model is only active after this date. */
+  promotion_start?: string;
+  /** Promotion end date (ISO 8601). If set, the model is disabled after this date. */
+  promotion_end?: string;
 };
 
 export function convertFromKiloModel(model: KiloFreeModel) {

src/lib/providers/openrouter/index.ts

@@ -60,7 +60,11 @@ function enhancedModelList(models: OpenRouterModel[]) {
         !kiloFreeModels.some(m => m.public_id === model.id && m.is_enabled) &&
         !isRateLimitedToDeath(model.id)
     )
-    .concat(kiloFreeModels.filter(m => m.is_enabled).map(model => convertFromKiloModel(model)))
+    .concat(
+      kiloFreeModels
+        .filter(m => m.is_enabled && !m.slackbot_only && !m.review_only)
+        .map(model => convertFromKiloModel(model))
+    )
     .concat([autoModel])
     .map((model: OpenRouterModel) => {
       const preferredIndex =

src/routers/admin-code-reviews-router.ts

@@ -1,8 +1,9 @@
 import { adminProcedure, createTRPCRouter } from '@/lib/trpc/init';
 import { db } from '@/lib/drizzle';
-import { cloud_agent_code_reviews, kilocode_users, organizations } from '@/db/schema';
+import { cloud_agent_code_reviews, cliSessions, kilocode_users, organizations } from '@/db/schema';
 import * as z from 'zod';
 import { sql, and, gte, lt, eq, isNotNull, desc, ilike, or, type SQL } from 'drizzle-orm';
+import { sonnet_46_free_review_model } from '@/lib/providers/anthropic';
 
 /**
  * SQL condition to exclude "Insufficient credits" errors from failure metrics.
@@ -371,4 +372,72 @@ export const adminCodeReviewsRouter = createTRPCRouter({
 
       return result;
     }),
+
+  // Sonnet 4.6 free review promotion tracking
+  getReviewPromotionStats: adminProcedure.query(async () => {
+    const promoModel = sonnet_46_free_review_model;
+    const promoStart = promoModel.promotion_start ?? '2026-02-18T00:00:00Z';
+    const promoEnd = promoModel.promotion_end ?? '2026-02-25T00:00:00Z';
+    const promoModelId = promoModel.internal_id;
+
+    // Query code reviews that used the promotional model during the promotion window
+    // Join with cli_sessions to check last_model
+    const result = await db
+      .select({
+        total_promo_reviews: sql<number>`COUNT(*)`,
+        completed_promo_reviews: sql<number>`COUNT(*) FILTER (WHERE ${cloud_agent_code_reviews.status} = 'completed')`,
+        failed_promo_reviews: sql<number>`COUNT(*) FILTER (WHERE ${cloud_agent_code_reviews.status} = 'failed')`,
+        unique_users: sql<number>`COUNT(DISTINCT COALESCE(${cloud_agent_code_reviews.owned_by_user_id}, ${cloud_agent_code_reviews.owned_by_organization_id}))`,
+        unique_orgs: sql<number>`COUNT(DISTINCT ${cloud_agent_code_reviews.owned_by_organization_id})`,
+      })
+      .from(cloud_agent_code_reviews)
+      .innerJoin(cliSessions, eq(cloud_agent_code_reviews.cli_session_id, cliSessions.session_id))
+      .where(
+        and(
+          gte(cloud_agent_code_reviews.created_at, promoStart),
+          lt(cloud_agent_code_reviews.created_at, promoEnd),
+          eq(cliSessions.last_model, promoModelId)
+        )
+      );
+
+    // Daily breakdown
+    const dailyBreakdown = await db
+      .select({
+        day: sql<string>`DATE_TRUNC('day', ${cloud_agent_code_reviews.created_at})::date::text`,
+        total: sql<number>`COUNT(*)`,
+        completed: sql<number>`COUNT(*) FILTER (WHERE ${cloud_agent_code_reviews.status} = 'completed')`,
+        unique_users: sql<number>`COUNT(DISTINCT COALESCE(${cloud_agent_code_reviews.owned_by_user_id}, ${cloud_agent_code_reviews.owned_by_organization_id}))`,
+      })
+      .from(cloud_agent_code_reviews)
+      .innerJoin(cliSessions, eq(cloud_agent_code_reviews.cli_session_id, cliSessions.session_id))
+      .where(
+        and(
+          gte(cloud_agent_code_reviews.created_at, promoStart),
+          lt(cloud_agent_code_reviews.created_at, promoEnd),
+          eq(cliSessions.last_model, promoModelId)
+        )
+      )
+      .groupBy(sql`DATE_TRUNC('day', ${cloud_agent_code_reviews.created_at})`)
+      .orderBy(sql`DATE_TRUNC('day', ${cloud_agent_code_reviews.created_at})`);
+
+    const stats = result[0];
+    return {
+      promotionModelId: promoModel.public_id,
+      promotionInternalModelId: promoModelId,
+      promotionStart: promoStart,
+      promotionEnd: promoEnd,
+      isActive: new Date() >= new Date(promoStart) && new Date() < new Date(promoEnd),
+      totalPromoReviews: Number(stats.total_promo_reviews) || 0,
+      completedPromoReviews: Number(stats.completed_promo_reviews) || 0,
+      failedPromoReviews: Number(stats.failed_promo_reviews) || 0,
+      uniqueUsers: Number(stats.unique_users) || 0,
+      uniqueOrgs: Number(stats.unique_orgs) || 0,
+      dailyBreakdown: dailyBreakdown.map(row => ({
+        day: row.day,
+        total: Number(row.total) || 0,
+        completed: Number(row.completed) || 0,
+        uniqueUsers: Number(row.unique_users) || 0,
+      })),
+    };
+  }),
 });