test(tools): check parameter schema surfaces

Generate JSON Schema from registered tool parameters so read-only and mutating root-pick surfaces stay intentional.

Author: AlbinoGeek

src/server/test-harness.ts

@@ -32,6 +32,7 @@ type ExecuteFn = (args: AnyRecord, context: AnyRecord) => Promise<string | AnyRe
 
 interface CapturedTool {
   name: string;
+  parameters?: unknown;
   execute: ExecuteFn;
 }
 
@@ -83,8 +84,11 @@ function makeFakeServer(): { server: FastMCP; tools: CapturedTool[] } {
   const tools: CapturedTool[] = [];
   const server = {
     sessions: [],
-    addTool(tool: { name: string; execute: ExecuteFn }) {
-      tools.push({ name: tool.name, execute: tool.execute });
+    addTool(tool: { name: string; parameters?: unknown; execute: ExecuteFn }) {
+      tools.push({ name: tool.name, parameters: tool.parameters, execute: tool.execute });
+    },
+    addResource() {
+      // Resource tests do not need transport behavior; tool-surface tests only need registration to complete.
     },
   } as unknown as FastMCP;
   return { server, tools };
@@ -120,3 +124,9 @@ export function captureTool(
     return JSON.stringify(result);
   };
 }
+
+export function captureToolDefinitions(register: (server: FastMCP) => void): CapturedTool[] {
+  const { server, tools } = makeFakeServer();
+  register(server);
+  return tools;
+}

src/server/tool-parameters.test.ts

@@ -0,0 +1,73 @@
+/**
+ * Tool parameter surface checks.
+ */
+
+import { describe, expect, test } from "bun:test";
+import { z } from "zod";
+import { captureToolDefinitions } from "./test-harness.js";
+import { registerRethunkGitTools } from "./tools.js";
+
+const READ_ONLY_ABSOLUTE_ROOT_TOOLS = [
+  "git_status",
+  "git_inventory",
+  "git_parity",
+  "list_presets",
+  "git_log",
+  "git_diff_summary",
+];
+
+const MUTATING_TOOLS = [
+  "batch_commit",
+  "git_push",
+  "git_merge",
+  "git_cherry_pick",
+  "git_reset_soft",
+  "git_worktree_add",
+  "git_worktree_remove",
+];
+
+const ALL_TOOLS = [...READ_ONLY_ABSOLUTE_ROOT_TOOLS, "git_worktree_list", ...MUTATING_TOOLS];
+
+type JsonObjectSchema = { properties?: Record<string, unknown>; required?: string[] };
+
+function toolSchemas(): Map<string, JsonObjectSchema> {
+  return new Map(
+    captureToolDefinitions(registerRethunkGitTools).map((tool) => [
+      tool.name,
+      z.toJSONSchema(tool.parameters as z.ZodType) as JsonObjectSchema,
+    ]),
+  );
+}
+
+describe("tool parameter schemas", () => {
+  test("generates JSON Schema for every registered tool", () => {
+    const schemas = toolSchemas();
+    expect([...schemas.keys()].sort()).toEqual([...ALL_TOOLS].sort());
+    for (const [name, schema] of schemas) {
+      expect(name.length).toBeGreaterThan(0);
+      expect(schema.properties).toBeDefined();
+    }
+  });
+
+  test("read-only batch tools expose absoluteGitRoots", () => {
+    const schemas = toolSchemas();
+    for (const name of READ_ONLY_ABSOLUTE_ROOT_TOOLS) {
+      expect(schemas.get(name)?.properties).toHaveProperty("absoluteGitRoots");
+    }
+  });
+
+  test("mutating tools do not expose absoluteGitRoots", () => {
+    const schemas = toolSchemas();
+    for (const name of MUTATING_TOOLS) {
+      expect(schemas.get(name)?.properties).not.toHaveProperty("absoluteGitRoots");
+    }
+  });
+
+  test("standalone git_push exposes push-only parameters", () => {
+    const schema = toolSchemas().get("git_push");
+    expect(schema?.properties).toHaveProperty("remote");
+    expect(schema?.properties).toHaveProperty("branch");
+    expect(schema?.properties).toHaveProperty("setUpstream");
+    expect(schema?.properties).not.toHaveProperty("commits");
+  });
+});