feat: add custom model context window override for all providers

- Add modelContextWindow field to base provider settings schema
- Implement applyModelOverrides method in BaseProvider class
- Update all provider implementations to apply context window override
- Add comprehensive tests for context window override functionality

This allows users to customize the context window size for any provider
to work around corporate upload limits or other restrictions.

Fixes #8397

.tmp/Roo-Code

@@ -0,0 +1 @@
+Subproject commit 86debeef43acbea9bdc1aa4b38d514541e164c91

.tmp/pr-8396

@@ -0,0 +1 @@
+Subproject commit a18538995de0f7d9cfc4a40d31380fb141d5604e

packages/types/src/provider-settings.ts

@@ -179,6 +179,9 @@ const baseProviderSettingsSchema = z.object({
 	modelMaxTokens: z.number().optional(),
 	modelMaxThinkingTokens: z.number().optional(),
 
+	// Model context window override.
+	modelContextWindow: z.number().optional(),
+
 	// Model verbosity.
 	verbosity: verbosityLevelsSchema.optional(),
 })

src/api/providers/__tests__/context-window-override.spec.ts

@@ -0,0 +1,126 @@
+import { describe, it, expect, beforeEach } from "vitest"
+import { AnthropicHandler } from "../anthropic"
+import { OpenRouterHandler } from "../openrouter"
+import { OpenAiHandler } from "../openai"
+import { GeminiHandler } from "../gemini"
+import type { ApiHandlerOptions } from "../../../shared/api"
+
+describe("Context Window Override", () => {
+	describe("AnthropicHandler", () => {
+		it("should apply modelContextWindow override", () => {
+			const options: ApiHandlerOptions = {
+				apiKey: "test-key",
+				apiModelId: "claude-3-5-sonnet-20241022",
+				modelContextWindow: 50000, // Custom context window
+			}
+
+			const handler = new AnthropicHandler(options)
+			const model = handler.getModel()
+
+			expect(model.info.contextWindow).toBe(50000)
+		})
+
+		it("should use default context window when no override is provided", () => {
+			const options: ApiHandlerOptions = {
+				apiKey: "test-key",
+				apiModelId: "claude-3-5-sonnet-20241022",
+			}
+
+			const handler = new AnthropicHandler(options)
+			const model = handler.getModel()
+
+			// Should use the default context window for this model
+			expect(model.info.contextWindow).toBe(200000)
+		})
+	})
+
+	describe("OpenRouterHandler", () => {
+		it("should apply modelContextWindow override", async () => {
+			const options: ApiHandlerOptions = {
+				openRouterApiKey: "test-key",
+				openRouterModelId: "anthropic/claude-3.5-sonnet",
+				modelContextWindow: 75000, // Custom context window
+			}
+
+			const handler = new OpenRouterHandler(options)
+			// Mock the models to avoid actual API calls
+			;(handler as any).models = {
+				"anthropic/claude-3.5-sonnet": {
+					contextWindow: 200000,
+					maxTokens: 8192,
+					supportsPromptCache: true,
+					supportsImages: true,
+				},
+			}
+
+			const model = handler.getModel()
+			expect(model.info.contextWindow).toBe(75000)
+		})
+	})
+
+	describe("OpenAiHandler", () => {
+		it("should apply modelContextWindow override to custom model info", () => {
+			const options: ApiHandlerOptions = {
+				openAiApiKey: "test-key",
+				openAiModelId: "gpt-4",
+				openAiCustomModelInfo: {
+					contextWindow: 128000,
+					maxTokens: 4096,
+					supportsPromptCache: false,
+					supportsImages: true,
+				},
+				modelContextWindow: 60000, // Custom context window
+			}
+
+			const handler = new OpenAiHandler(options)
+			const model = handler.getModel()
+
+			expect(model.info.contextWindow).toBe(60000)
+		})
+	})
+
+	describe("GeminiHandler", () => {
+		it("should apply modelContextWindow override", () => {
+			const options: ApiHandlerOptions = {
+				geminiApiKey: "test-key",
+				apiModelId: "gemini-1.5-pro-latest",
+				modelContextWindow: 100000, // Custom context window
+			}
+
+			const handler = new GeminiHandler(options)
+			const model = handler.getModel()
+
+			expect(model.info.contextWindow).toBe(100000)
+		})
+	})
+
+	describe("Edge cases", () => {
+		it("should not apply override when modelContextWindow is 0", () => {
+			const options: ApiHandlerOptions = {
+				apiKey: "test-key",
+				apiModelId: "claude-3-5-sonnet-20241022",
+				modelContextWindow: 0, // Zero should not override
+			}
+
+			const handler = new AnthropicHandler(options)
+			const model = handler.getModel()
+
+			// Should use the default context window
+			expect(model.info.contextWindow).toBe(200000)
+		})
+
+		it("should not apply override when modelContextWindow is negative", () => {
+			const options: ApiHandlerOptions = {
+				apiKey: "test-key",
+				apiModelId: "claude-3-5-sonnet-20241022",
+				modelContextWindow: -1000, // Negative should not override
+			}
+
+			const handler = new AnthropicHandler(options)
+			const model = handler.getModel()
+
+			// Should use the default context window
+			expect(model.info.contextWindow).toBe(200000)
+		})
+	})
+})

src/api/providers/anthropic.ts

@@ -264,6 +264,9 @@ export class AnthropicHandler extends BaseProvider implements SingleCompletionHa
 			}
 		}
 
+		// Apply user-configured overrides (e.g., custom context window)
+		info = this.applyModelOverrides(info, this.options)
+
 		const params = getModelParams({
 			format: "anthropic",
 			modelId: id,

src/api/providers/base-openai-compatible-provider.ts

@@ -140,6 +140,9 @@ export abstract class BaseOpenAiCompatibleProvider<ModelName extends string>
 				? (this.options.apiModelId as ModelName)
 				: this.defaultProviderModelId
 
-		return { id, info: this.providerModels[id] }
+		// Apply user-configured overrides (e.g., custom context window)
+		const info = this.applyModelOverrides(this.providerModels[id], this.options)
+
+		return { id, info }
 	}
 }

src/api/providers/base-provider.ts

@@ -3,6 +3,7 @@ import { Anthropic } from "@anthropic-ai/sdk"
 import type { ModelInfo } from "@roo-code/types"
 
 import type { ApiHandler, ApiHandlerCreateMessageMetadata } from "../index"
+import type { ApiHandlerOptions } from "../../shared/api"
 import { ApiStream } from "../transform/stream"
 import { countTokens } from "../../utils/countTokens"
 
@@ -18,6 +19,26 @@ export abstract class BaseProvider implements ApiHandler {
 
 	abstract getModel(): { id: string; info: ModelInfo }
 
+	/**
+	 * Applies user-configured overrides to model info.
+	 * This allows users to customize model parameters like context window size
+	 * to work around corporate restrictions or other limitations.
+	 *
+	 * @param info The original model info
+	 * @param options The API handler options containing user overrides
+	 * @returns The model info with overrides applied
+	 */
+	protected applyModelOverrides(info: ModelInfo, options: ApiHandlerOptions): ModelInfo {
+		const overriddenInfo = { ...info }
+
+		// Apply context window override if specified
+		if (options.modelContextWindow && options.modelContextWindow > 0) {
+			overriddenInfo.contextWindow = options.modelContextWindow
+		}
+
+		return overriddenInfo
+	}
+
 	/**
 	 * Default token counting implementation using tiktoken.
 	 * Providers can override this to use their native token counting endpoints.

src/api/providers/bedrock.ts

@@ -373,7 +373,7 @@ export class AwsBedrockHandler extends BaseProvider implements SingleCompletionH
 			maxTokens: modelConfig.maxTokens || (modelConfig.info.maxTokens as number),
 			temperature: modelConfig.temperature ?? (this.options.modelTemperature as number),
 		}
-	
+
 		// Check if 1M context is enabled for Claude Sonnet 4
 		// Use parseBaseModelId to handle cross-region inference prefixes
 		const baseModelId = this.parseBaseModelId(modelConfig.id)
@@ -922,10 +922,14 @@ export class AwsBedrockHandler extends BaseProvider implements SingleCompletionH
 		if (this.options.modelMaxTokens && this.options.modelMaxTokens > 0) {
 			model.info.maxTokens = this.options.modelMaxTokens
 		}
+		// Support both awsModelContextWindow (for backward compatibility) and modelContextWindow
 		if (this.options.awsModelContextWindow && this.options.awsModelContextWindow > 0) {
 			model.info.contextWindow = this.options.awsModelContextWindow
 		}
 
+		// Apply general model overrides (including modelContextWindow)
+		model.info = this.applyModelOverrides(model.info, this.options)
+
 		return model
 	}
 
@@ -983,6 +987,9 @@ export class AwsBedrockHandler extends BaseProvider implements SingleCompletionH
 			}
 		}
 
+		// Apply general model overrides (including modelContextWindow) after all specific logic
+		modelConfig.info = this.applyModelOverrides(modelConfig.info, this.options)
+
 		// Get model params including reasoning configuration
 		const params = getModelParams({
 			format: "anthropic",

src/api/providers/gemini.ts

@@ -166,6 +166,10 @@ export class GeminiHandler extends BaseProvider implements SingleCompletionHandl
 		const modelId = this.options.apiModelId
 		let id = modelId && modelId in geminiModels ? (modelId as GeminiModelId) : geminiDefaultModelId
 		let info: ModelInfo = geminiModels[id]
+
+		// Apply user-configured overrides (e.g., custom context window)
+		info = this.applyModelOverrides(info, this.options)
+
 		const params = getModelParams({ format: "gemini", modelId: id, model: info, settings: this.options })
 
 		// The `:thinking` suffix indicates that the model is a "Hybrid"

src/api/providers/openai.ts

@@ -267,7 +267,11 @@ export class OpenAiHandler extends BaseProvider implements SingleCompletionHandl
 
 	override getModel() {
 		const id = this.options.openAiModelId ?? ""
-		const info = this.options.openAiCustomModelInfo ?? openAiModelInfoSaneDefaults
+		let info = this.options.openAiCustomModelInfo ?? openAiModelInfoSaneDefaults
+
+		// Apply user-configured overrides (e.g., custom context window)
+		info = this.applyModelOverrides(info, this.options)
+
 		const params = getModelParams({ format: "openai", modelId: id, model: info, settings: this.options })
 		return { id, info, ...params }
 	}

src/api/providers/openrouter.ts

@@ -232,6 +232,9 @@ export class OpenRouterHandler extends BaseProvider implements SingleCompletionH
 			info = this.endpoints[this.options.openRouterSpecificProvider]
 		}
 
+		// Apply user-configured overrides (e.g., custom context window)
+		info = this.applyModelOverrides(info, this.options)
+
 		const isDeepSeekR1 = id.startsWith("deepseek/deepseek-r1") || id === "perplexity/sonar-reasoning"
 
 		const params = getModelParams({

src/api/providers/router-provider.ts

@@ -63,9 +63,13 @@ export abstract class RouterProvider extends BaseProvider {
 	override getModel(): { id: string; info: ModelInfo } {
 		const id = this.modelId ?? this.defaultModelId
 
-		return this.models[id]
-			? { id, info: this.models[id] }
-			: { id: this.defaultModelId, info: this.defaultModelInfo }
+		// Get the base model info
+		const baseInfo = this.models[id] ? this.models[id] : this.defaultModelInfo
+
+		// Apply user-configured overrides (e.g., custom context window)
+		const info = this.applyModelOverrides(baseInfo, this.options)
+
+		return { id: this.models[id] ? id : this.defaultModelId, info }
 	}
 
 	protected supportsTemperature(modelId: string): boolean {