fix(web): disambiguate MCP language model selection for ask_codebase

CHANGELOG.md

@@ -62,6 +62,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - [EE] Fixed connector setup dialogs to add scrolling when connector setup content goes out of view.
 - Fixed Gitea sync failing with `ERR_STREAM_PREMATURE_CLOSE` by forcing identity encoding on the Gitea API fetch and guarding against null repository responses. [#1405](https://github.com/sourcebot-dev/sourcebot/pull/1405)
 - [EE] Fixed Ask connector MCP tools with provider-invalid names failing to run by sanitizing model-facing tool names while preserving raw names in the UI.
+- [EE] Fixed `ask_codebase` language model selection to match configured models by `provider` and `model`, only requiring `displayName` when multiple configurations share the same pair. [#1414](https://github.com/sourcebot-dev/sourcebot/pull/1414)
+
 
 ## [5.0.4] - 2026-06-18
 

packages/web/src/ee/features/mcp/askCodebase.test.ts

@@ -0,0 +1,102 @@
+import { ErrorCode } from "@/lib/errorCodes";
+import { StatusCodes } from "http-status-codes";
+import { describe, expect, it } from "vitest";
+import { selectConfiguredLanguageModel } from "./selectConfiguredLanguageModel";
+
+type ConfiguredLanguageModel = Parameters<typeof selectConfiguredLanguageModel>[0][number];
+
+const createConfiguredModel = (overrides: Partial<{
+    provider: string;
+    model: string;
+    displayName?: string;
+}> = {}) => ({
+    provider: 'anthropic',
+    model: 'claude-opus-4-7',
+    displayName: 'Claude Opus 4.7',
+    ...overrides,
+}) as ConfiguredLanguageModel;
+
+describe("selectConfiguredLanguageModel", () => {
+    it("matches a configured model by provider and model when displayName is omitted", () => {
+        const configuredModel = createConfiguredModel();
+
+        const result = selectConfiguredLanguageModel(
+            [configuredModel],
+            { provider: configuredModel.provider, model: configuredModel.model }
+        );
+
+        expect(result).toEqual({ languageModelConfig: configuredModel });
+    });
+
+    it("uses displayName to disambiguate duplicate provider/model entries", () => {
+        const firstModel = createConfiguredModel({ displayName: 'Claude Opus 4.7 (slow)' });
+        const secondModel = createConfiguredModel({ displayName: 'Claude Opus 4.7 (fast)' });
+
+        const result = selectConfiguredLanguageModel(
+            [firstModel, secondModel],
+            {
+                provider: firstModel.provider,
+                model: firstModel.model,
+                displayName: secondModel.displayName,
+            }
+        );
+
+        expect(result).toEqual({ languageModelConfig: secondModel });
+    });
+
+    it("returns an error when no configured model matches provider and model", () => {
+        const configuredModel = createConfiguredModel();
+
+        const result = selectConfiguredLanguageModel(
+            [configuredModel],
+            { provider: 'openai', model: 'gpt-5' }
+        );
+
+        expect(result).toEqual({
+            error: {
+                statusCode: StatusCodes.BAD_REQUEST,
+                errorCode: ErrorCode.INVALID_REQUEST_BODY,
+                message: "Language model 'openai/gpt-5' is not configured.",
+            },
+        });
+    });
+
+    it("returns a disambiguation error when multiple configured models match", () => {
+        const firstModel = createConfiguredModel({ displayName: 'Claude Opus 4.7 (slow)' });
+        const secondModel = createConfiguredModel({ displayName: 'Claude Opus 4.7 (fast)' });
+
+        const result = selectConfiguredLanguageModel(
+            [firstModel, secondModel],
+            { provider: firstModel.provider, model: firstModel.model }
+        );
+
+        expect(result).toEqual({
+            error: {
+                statusCode: StatusCodes.BAD_REQUEST,
+                errorCode: ErrorCode.INVALID_REQUEST_BODY,
+                message: "Language model 'anthropic/claude-opus-4-7' matches multiple configured models. Pass displayName to disambiguate. Available matches: 'Claude Opus 4.7 (slow)', 'Claude Opus 4.7 (fast)'.",
+            },
+        });
+    });
+
+    it("returns an error when displayName does not match any configured model", () => {
+        const configuredModel = createConfiguredModel();
+
+        const result = selectConfiguredLanguageModel(
+            [configuredModel],
+            {
+                provider: configuredModel.provider,
+                model: configuredModel.model,
+                displayName: 'Claude Sonnet 4.6',
+            }
+        );
+
+        expect(result).toEqual({
+            error: {
+                statusCode: StatusCodes.BAD_REQUEST,
+                errorCode: ErrorCode.INVALID_REQUEST_BODY,
+                message: "Language model 'anthropic/claude-opus-4-7' is configured, but not with displayName 'Claude Sonnet 4.6'. Available matches: 'Claude Opus 4.7'.",
+            },
+        });
+    });
+});

packages/web/src/ee/features/mcp/askCodebase.ts

@@ -4,7 +4,7 @@ import { generateChatNameFromMessage } from "@/ee/features/chat/llm.server";
 import { getAISDKLanguageModelAndOptions } from "@/features/chat/llm.server";
 import { resolveContextWindow } from "@/features/chat/modelContextWindow.server";
 import { LanguageModelInfo, SBChatMessage, SearchScope } from "@/features/chat/types";
-import { convertLLMOutputToPortableMarkdown, getAnswerPartFromAssistantMessage, getLanguageModelKey } from "@/features/chat/utils";
+import { convertLLMOutputToPortableMarkdown, getAnswerPartFromAssistantMessage } from "@/features/chat/utils";
 import { resolveModelCapabilities } from "@/features/chat/modelCapabilities.server";
 import { ErrorCode } from "@/lib/errorCodes";
 import { ServiceError, ServiceErrorException } from "@/lib/serviceError";
@@ -18,6 +18,7 @@ import { captureEvent } from "@/lib/posthog";
 import { createAudit } from "@/ee/features/audit/audit";
 import { createMessageStream } from "@/ee/features/chat/agent";
 import { getPromptCacheStrategy } from "@/ee/features/chat/promptCaching";
+import { selectConfiguredLanguageModel } from "@/ee/features/mcp/selectConfiguredLanguageModel";
 
 const logger = createLogger('ask-codebase-api');
 
@@ -71,17 +72,14 @@ export const askCodebase = (params: AskCodebaseParams): Promise<AskCodebaseResul
 
             let languageModelConfig = configuredModels[0];
             if (requestedLanguageModel) {
-                const matchingModel = configuredModels.find(
-                    (m) => getLanguageModelKey(m) === getLanguageModelKey(requestedLanguageModel)
+                const result = selectConfiguredLanguageModel(
+                    configuredModels,
+                    requestedLanguageModel
                 );
-                if (!matchingModel) {
-                    return {
-                        statusCode: StatusCodes.BAD_REQUEST,
-                        errorCode: ErrorCode.INVALID_REQUEST_BODY,
-                        message: `Language model '${requestedLanguageModel.provider}/${requestedLanguageModel.model}' is not configured.`,
-                    } satisfies ServiceError;
+                if (result.error) {
+                    return result.error;
                 }
-                languageModelConfig = matchingModel;
+                languageModelConfig = result.languageModelConfig;
             }
 
             const { model, providerOptions, temperature } = await getAISDKLanguageModelAndOptions(languageModelConfig);

packages/web/src/ee/features/mcp/selectConfiguredLanguageModel.ts

@@ -0,0 +1,62 @@
+import { LanguageModelInfo } from "@/features/chat/types";
+import { ErrorCode } from "@/lib/errorCodes";
+import { ServiceError } from "@/lib/serviceError";
+import { StatusCodes } from "http-status-codes";
+
+const formatLanguageModelName = (model: Pick<LanguageModelInfo, 'provider' | 'model'>) =>
+    `${model.provider}/${model.model}`;
+
+const formatConfiguredLanguageModelLabel = (model: Pick<LanguageModelInfo, 'provider' | 'model' | 'displayName'>) =>
+    model.displayName ? `'${model.displayName}'` : formatLanguageModelName(model);
+
+export const selectConfiguredLanguageModel = <T extends Pick<LanguageModelInfo, 'provider' | 'model' | 'displayName'>>(
+    configuredModels: T[],
+    requestedLanguageModel: Pick<LanguageModelInfo, 'provider' | 'model' | 'displayName'>
+): (
+    | { languageModelConfig: T; error?: never }
+    | { languageModelConfig?: never; error: ServiceError }
+) => {
+    const candidateModels = configuredModels.filter(
+        (model) => model.provider === requestedLanguageModel.provider && model.model === requestedLanguageModel.model
+    );
+    if (candidateModels.length === 0) {
+        return {
+            error: {
+                statusCode: StatusCodes.BAD_REQUEST,
+                errorCode: ErrorCode.INVALID_REQUEST_BODY,
+                message: `Language model '${formatLanguageModelName(requestedLanguageModel)}' is not configured.`,
+            } satisfies ServiceError,
+        };
+    }
+
+    if (requestedLanguageModel.displayName) {
+        const matchingModel = candidateModels.find(
+            (model) => model.displayName === requestedLanguageModel.displayName
+        );
+        if (!matchingModel) {
+            const availableDisplayNames = candidateModels.map(formatConfiguredLanguageModelLabel).join(', ');
+            return {
+                error: {
+                    statusCode: StatusCodes.BAD_REQUEST,
+                    errorCode: ErrorCode.INVALID_REQUEST_BODY,
+                    message: `Language model '${formatLanguageModelName(requestedLanguageModel)}' is configured, but not with displayName '${requestedLanguageModel.displayName}'. Available matches: ${availableDisplayNames}.`,
+                } satisfies ServiceError,
+            };
+        }
+
+        return { languageModelConfig: matchingModel };
+    }
+
+    if (candidateModels.length > 1) {
+        const availableDisplayNames = candidateModels.map(formatConfiguredLanguageModelLabel).join(', ');
+        return {
+            error: {
+                statusCode: StatusCodes.BAD_REQUEST,
+                errorCode: ErrorCode.INVALID_REQUEST_BODY,
+                message: `Language model '${formatLanguageModelName(requestedLanguageModel)}' matches multiple configured models. Pass displayName to disambiguate. Available matches: ${availableDisplayNames}.`,
+            } satisfies ServiceError,
+        };
+    }
+
+    return { languageModelConfig: candidateModels[0] };
+};