chore: adjust override behavior

Author: gagik

src/common/config/configUtils.ts

@@ -113,11 +113,10 @@ export function commaSeparatedToArray<T extends string[]>(str: string | string[]
  */
 export function parseBoolean(val: unknown): unknown {
     if (typeof val === "string") {
-        const lower = val.toLowerCase().trim();
-        if (lower === "false") {
+        if (val === "false") {
             return false;
         }
-        if (lower === "true") {
+        if (val === "true") {
             return true;
         }
         throw new Error(`Invalid boolean value: ${val}`);
@@ -134,7 +133,10 @@ export function parseBoolean(val: unknown): unknown {
 /** Allow overriding only to the allowed value */
 export function oneWayOverride<T>(allowedValue: T): CustomOverrideLogic {
     return (oldValue, newValue) => {
-        // Only allow override if setting to allowed value
+        // Only allow override if setting to allowed value or current value
+        if (newValue === oldValue) {
+            return newValue;
+        }
         if (newValue === allowedValue) {
             return newValue;
         }

src/common/config/userConfig.ts

@@ -183,11 +183,12 @@ export const UserConfigSchema = z4.object({
         .describe(
             "API key for Voyage AI embeddings service (required for vector search operations with text-to-embedding conversion)."
         )
-        .register(configRegistry, { isSecret: true }),
+        .register(configRegistry, { isSecret: true, overrideBehavior: "override" }),
     embeddingsValidation: z4
         .preprocess(parseBoolean, z4.boolean())
         .default(true)
-        .describe("When set to false, disables validation of embeddings dimensions."),
+        .describe("When set to false, disables validation of embeddings dimensions.")
+        .register(configRegistry, { overrideBehavior: oneWayOverride(true) }),
     vectorSearchDimensions: z4.coerce
         .number()
         .default(1024)

tests/unit/common/config/configOverrides.test.ts

@@ -14,7 +14,7 @@ describe("configOverrides", () => {
         connectionString: "mongodb://localhost:27017",
         vectorSearchDimensions: 1024,
         vectorSearchSimilarityFunction: "euclidean",
-        disableEmbeddingsValidation: false,
+        embeddingsValidation: false,
         previewFeatures: [],
         loggers: ["disk", "mcp"],
         exportTimeoutMs: 300_000,
@@ -63,6 +63,41 @@ describe("configOverrides", () => {
             expect(result).toEqual(baseConfig);
         });
 
+        describe("boolean edge cases", () => {
+            it("should parse correctly for true value", () => {
+                const request: RequestContext = {
+                    headers: {
+                        "x-mongodb-mcp-read-only": "true",
+                    },
+                };
+                const result = applyConfigOverrides({ baseConfig: baseConfig as UserConfig, request });
+                expect(result.readOnly).toBe(true);
+            });
+
+            it("should parse correctly for false value", () => {
+                const request: RequestContext = {
+                    headers: {
+                        "x-mongodb-mcp-read-only": "false",
+                    },
+                };
+                const result = applyConfigOverrides({ baseConfig: baseConfig as UserConfig, request });
+                expect(result.readOnly).toBe(false);
+            });
+
+            for (const value of ["True", "False", "TRUE", "FALSE", "0", "1", ""]) {
+                it(`should throw an error for ${value}`, () => {
+                    const request: RequestContext = {
+                        headers: {
+                            "x-mongodb-mcp-read-only": value,
+                        },
+                    };
+                    expect(() => applyConfigOverrides({ baseConfig: baseConfig as UserConfig, request })).toThrow(
+                        `Invalid boolean value: ${value}`
+                    );
+                });
+            }
+        });
+
         it("should return base config when request has no headers or query", () => {
             const result = applyConfigOverrides({ baseConfig: baseConfig as UserConfig, request: {} });
             expect(result).toEqual(baseConfig);
@@ -256,7 +291,7 @@ describe("configOverrides", () => {
                     "notificationTimeoutMs",
                     "exportTimeoutMs",
                     "atlasTemporaryDatabaseUserLifetimeMs",
-                    "disableEmbeddingsValidation",
+                    "embeddingsValidation",
                     "previewFeatures",
                 ]);
             });
@@ -294,22 +329,22 @@ describe("configOverrides", () => {
             });
 
             it("should allow disableEmbeddingsValidation override from true to false", () => {
-                const request: RequestContext = { headers: { "x-mongodb-mcp-disable-embeddings-validation": "false" } };
+                const request: RequestContext = { headers: { "x-mongodb-mcp-embeddings-validation": "true" } };
                 const result = applyConfigOverrides({
-                    baseConfig: { ...baseConfig, disableEmbeddingsValidation: true } as UserConfig,
+                    baseConfig: { ...baseConfig, embeddingsValidation: true } as UserConfig,
                     request,
                 });
-                expect(result.disableEmbeddingsValidation).toBe(false);
+                expect(result.embeddingsValidation).toBe(true);
             });
 
-            it("should throw when trying to override disableEmbeddingsValidation from false to true", () => {
-                const request: RequestContext = { headers: { "x-mongodb-mcp-disable-embeddings-validation": "true" } };
+            it("should throw when trying to override embeddingsValidation from false to true", () => {
+                const request: RequestContext = { headers: { "x-mongodb-mcp-embeddings-validation": "false" } };
                 expect(() =>
                     applyConfigOverrides({
-                        baseConfig: { ...baseConfig, disableEmbeddingsValidation: false } as UserConfig,
+                        baseConfig: { ...baseConfig, embeddingsValidation: true } as UserConfig,
                         request,
                     })
-                ).toThrow("Cannot apply override for disableEmbeddingsValidation: Can only set to false");
+                ).toThrow("Cannot apply override for embeddingsValidation: Can only set to true");
             });
         });