Initialize parameter values to default values (#1363)

Related PR: braintrustdata/braintrust#10788

After some recent discussions, I've realized that parameter data should
be initialized to your default values. This is largely because when we
open a parameter within our UI, we want to show the default values
within forms without rendering forms in a dirty state.

Here is a demo of parameter creation:


https://github.com/user-attachments/assets/0bd28948-843b-41c0-bf0d-e1a2d39ccce2

Bumped the SDK version because I would like to release and share this
with customers ASAP.

Author: joshuawootonn

js/package.json

@@ -1,6 +1,6 @@
 {
   "name": "braintrust",
-  "version": "2.2.1",
+  "version": "2.2.2",
   "description": "SDK for integrating Braintrust",
   "repository": {
     "type": "git",

js/src/framework.test.ts

@@ -992,6 +992,111 @@ describe("framework2 metadata support", () => {
     });
   });
 
+  describe("CodeParameters defaults", () => {
+    test("toFunctionDefinition initializes data with schema defaults", async () => {
+      const project = projects.create({ name: "test-project" });
+      project.parameters.create({
+        name: "test-parameters",
+        schema: {
+          title: z.string().default("default-title"),
+          numSamples: z.number().default(10),
+          enabled: z.boolean().default(true),
+          tags: z.array(z.string()).default(["default-tag"]),
+          config: z
+            .object({
+              retryCount: z.number(),
+              strategy: z.string(),
+            })
+            .default({
+              retryCount: 3,
+              strategy: "balanced",
+            }),
+          datasetName: z.string(),
+          main: {
+            type: "prompt",
+            default: {
+              messages: [{ role: "user", content: "{{input}}" }],
+              model: "gpt-4",
+            },
+          },
+        },
+      });
+
+      // eslint-disable-next-line @typescript-eslint/no-explicit-any
+      const parameters = (project as any)._publishableParameters;
+      expect(parameters).toHaveLength(1);
+
+      const mockProjectMap = {
+        resolve: vi.fn().mockResolvedValue("project-123"),
+        // eslint-disable-next-line @typescript-eslint/no-explicit-any
+      } as any;
+
+      const funcDef = await parameters[0].toFunctionDefinition(mockProjectMap);
+
+      expect(funcDef.function_data.type).toBe("parameters");
+      expect(funcDef.function_data.data).toMatchObject({
+        title: "default-title",
+        numSamples: 10,
+        enabled: true,
+        tags: ["default-tag"],
+        config: {
+          retryCount: 3,
+          strategy: "balanced",
+        },
+        main: {
+          prompt: {
+            type: "chat",
+            messages: [{ role: "user", content: "{{input}}" }],
+          },
+          options: {
+            model: "gpt-4",
+          },
+        },
+      });
+      expect(funcDef.function_data.data).not.toHaveProperty("datasetName");
+    });
+
+    test("toFunctionDefinition does not initialize data when schema has no defaults", async () => {
+      const project = projects.create({ name: "test-project" });
+      project.parameters.create({
+        name: "test-parameters-no-defaults",
+        schema: {
+          title: z.string(),
+          numSamples: z.number(),
+          enabled: z.boolean(),
+          tags: z.array(z.string()),
+          config: z.object({
+            retryCount: z.number(),
+            strategy: z.string(),
+          }),
+          main: {
+            type: "prompt",
+          },
+        },
+      });
+
+      // eslint-disable-next-line @typescript-eslint/no-explicit-any
+      const parameters = (project as any)._publishableParameters;
+      expect(parameters).toHaveLength(1);
+
+      const mockProjectMap = {
+        resolve: vi.fn().mockResolvedValue("project-123"),
+        // eslint-disable-next-line @typescript-eslint/no-explicit-any
+      } as any;
+
+      const funcDef = await parameters[0].toFunctionDefinition(mockProjectMap);
+
+      expect(funcDef.function_data.type).toBe("parameters");
+      expect(funcDef.function_data.data).toEqual({});
+      expect(funcDef.function_data.data).not.toHaveProperty("title");
+      expect(funcDef.function_data.data).not.toHaveProperty("numSamples");
+      expect(funcDef.function_data.data).not.toHaveProperty("enabled");
+      expect(funcDef.function_data.data).not.toHaveProperty("tags");
+      expect(funcDef.function_data.data).not.toHaveProperty("config");
+      expect(funcDef.function_data.data).not.toHaveProperty("main");
+    });
+  });
+
   describe("Scorer metadata", () => {
     test("code scorer stores metadata correctly", () => {
       const project = projects.create({ name: "test-project" });

js/src/framework2.ts

@@ -617,6 +617,7 @@ export class CodeParameters {
   async toFunctionDefinition(
     projectNameToId: ProjectNameIdMap,
   ): Promise<FunctionEvent> {
+    const schema = serializeEvalParameterstoParametersSchema(this.schema);
     return {
       project_id: await projectNameToId.resolve(this.project),
       name: this.name,
@@ -625,8 +626,8 @@ export class CodeParameters {
       function_type: "parameters",
       function_data: {
         type: "parameters",
-        data: {},
-        __schema: serializeEvalParameterstoParametersSchema(this.schema),
+        data: getDefaultDataFromParametersSchema(schema),
+        __schema: schema,
       },
       if_exists: this.ifExists,
       metadata: this.metadata,
@@ -738,6 +739,20 @@ export function serializeEvalParameterstoParametersSchema(
   };
 }
 
+function getDefaultDataFromParametersSchema(
+  schema: ParametersSchema,
+): Record<string, unknown> {
+  return Object.fromEntries(
+    Object.entries(schema.properties).flatMap(([name, value]) => {
+      if (!("default" in value)) {
+        return [];
+      }
+
+      return [[name, value.default]];
+    }),
+  );
+}
+
 export function serializeRemoteEvalParametersContainer(
   parameters: EvalParameters | RemoteEvalParameters<boolean, boolean>,
 ): SerializedParametersContainer {