diff --git a/src/cli/dynamic-commands.ts b/src/cli/dynamic-commands.ts
index e3f438b..fd6b3eb 100644
--- a/src/cli/dynamic-commands.ts
+++ b/src/cli/dynamic-commands.ts
@@ -5,6 +5,7 @@ import { validateResponse } from "../validator/schema.js";
 import { filterPii } from "@lucianfialho/pii-filter";
 import { printDryRun } from "./dry-run.js";
 import { simplifyName } from "./agent-help.js";
+import { sanitizeCommandName, uniqueName } from "./sanitize.js";
 import type { RuntimeConfig } from "../executor/types.js";
 import type { OperationGroup, OpenAPISpec } from "../parser/types.js";
 
@@ -14,8 +15,10 @@ export function buildDynamicCommands(
   config: RuntimeConfig,
   spec?: OpenAPISpec
 ): void {
+  const usedNames = new Set<string>();
   for (const group of groups) {
-    const groupCmd = prog.command(group.tag).description(group.description);
+    const groupName = uniqueName(sanitizeCommandName(group.tag), usedNames);
+    const groupCmd = prog.command(groupName).description(group.description);
 
     for (const op of group.operations) {
       const cmdName = simplifyName(op.id, group.tag);
diff --git a/src/cli/sanitize.ts b/src/cli/sanitize.ts
new file mode 100644
index 0000000..54db9f3
--- /dev/null
+++ b/src/cli/sanitize.ts
@@ -0,0 +1,11 @@
+export function sanitizeCommandName(name: string): string {
+  return name.toLowerCase().replace(/[^a-z0-9]+/g, "-").replace(/^-+|-+$/g, "") || "group";
+}
+
+export function uniqueName(name: string, used: Set<string>): string {
+  let candidate = name;
+  let n = 2;
+  while (used.has(candidate)) candidate = `${name}-${n++}`;
+  used.add(candidate);
+  return candidate;
+}
diff --git a/src/executor/commander-builder.json-params.test.ts b/src/executor/commander-builder.json-params.test.ts
new file mode 100644
index 0000000..de49731
--- /dev/null
+++ b/src/executor/commander-builder.json-params.test.ts
@@ -0,0 +1,137 @@
+import { describe, it, expect, vi, beforeEach } from "vitest";
+import { Command } from "commander";
+import { loadSpec } from "../parser/loader.js";
+import { buildCommands } from "./commander-builder.js";
+import type { RuntimeConfig } from "./types.js";
+import path from "node:path";
+
+const FIXTURE = path.resolve("test/fixtures/petstore.yaml");
+
+const config: RuntimeConfig = {
+  specPath: FIXTURE,
+  baseUrl: "https://example.com",
+  auth: { type: "none", value: "" },
+  output: "json",
+  verbose: false,
+  quiet: false,
+  dryRun: false,
+  validate: false,
+};
+
+describe("collectParams JSON parsing", () => {
+  beforeEach(() => {
+    vi.restoreAllMocks();
+  });
+
+  it("parses object params from JSON strings", async () => {
+    const op: Operation = {
+      id: "createVideos",
+      method: "POST",
+      path: "/videos",
+      summary: "Create video",
+      description: "",
+      params: [
+        { name: "name", in: "body", type: "string", required: true, description: "" },
+        { name: "content", in: "body", type: "object", required: true, description: "" },
+      ],
+      bodyRequired: true,
+      security: [],
+    };
+
+    let capturedBody: unknown;
+    vi.stubGlobal("fetch", vi.fn().mockImplementation((_url: string, init: RequestInit) => {
+      capturedBody = JSON.parse(init.body as string);
+      return Promise.resolve({
+        status: 200,
+        statusText: "OK",
+        headers: new Map([["content-type", "application/json"]]),
+        text: () => Promise.resolve("{}"),
+      });
+    }));
+
+    const spec = await loadSpec(FIXTURE);
+    const program = new Command();
+    program.exitOverride();
+    buildCommands(program, [{ tag: "Videos", description: "", operations: [op] }], config, spec);
+
+    await program.parseAsync(["node", "test", "videos", "create", "--name", "Test", "--content", '{"text":"hello"}']);
+
+    expect(capturedBody).toEqual({ name: "Test", content: { text: "hello" } });
+
+    vi.unstubAllGlobals();
+  });
+
+  it("parses array params from JSON strings", async () => {
+    const op: Operation = {
+      id: "createItem",
+      method: "POST",
+      path: "/items",
+      summary: "Create items",
+      description: "",
+      params: [
+        { name: "tags", in: "body", type: "array", required: true, description: "" },
+      ],
+      bodyRequired: true,
+      security: [],
+    };
+
+    let capturedBody: unknown;
+    vi.stubGlobal("fetch", vi.fn().mockImplementation((_url: string, init: RequestInit) => {
+      capturedBody = JSON.parse(init.body as string);
+      return Promise.resolve({
+        status: 200,
+        statusText: "OK",
+        headers: new Map([["content-type", "application/json"]]),
+        text: () => Promise.resolve("{}"),
+      });
+    }));
+
+    const spec = await loadSpec(FIXTURE);
+    const program = new Command();
+    program.exitOverride();
+    buildCommands(program, [{ tag: "Items", description: "", operations: [op] }], config, spec);
+
+    await program.parseAsync(["node", "test", "items", "create", "--tags", '["a","b"]']);
+
+    expect(capturedBody).toEqual({ tags: ["a", "b"] });
+
+    vi.unstubAllGlobals();
+  });
+
+  it("falls back to string when JSON parse fails", async () => {
+    const op: Operation = {
+      id: "createThings",
+      method: "POST",
+      path: "/things",
+      summary: "Create thing",
+      description: "",
+      params: [
+        { name: "data", in: "body", type: "object", required: true, description: "" },
+      ],
+      bodyRequired: true,
+      security: [],
+    };
+
+    let capturedBody: unknown;
+    vi.stubGlobal("fetch", vi.fn().mockImplementation((_url: string, init: RequestInit) => {
+      capturedBody = JSON.parse(init.body as string);
+      return Promise.resolve({
+        status: 200,
+        statusText: "OK",
+        headers: new Map([["content-type", "application/json"]]),
+        text: () => Promise.resolve("{}"),
+      });
+    }));
+
+    const spec = await loadSpec(FIXTURE);
+    const program = new Command();
+    program.exitOverride();
+    buildCommands(program, [{ tag: "Things", description: "", operations: [op] }], config, spec);
+
+    await program.parseAsync(["node", "test", "things", "create", "--data", "not-json"]);
+
+    expect(capturedBody).toEqual({ data: "not-json" });
+
+    vi.unstubAllGlobals();
+  });
+});
diff --git a/src/executor/commander-builder.test.ts b/src/executor/commander-builder.test.ts
index 07bed14..0a67538 100644
--- a/src/executor/commander-builder.test.ts
+++ b/src/executor/commander-builder.test.ts
@@ -107,120 +107,3 @@ describe("buildCommands", () => {
   });
 });
 
-describe("collectParams JSON parsing", () => {
-  beforeEach(() => {
-    vi.restoreAllMocks();
-  });
-
-  it("parses object params from JSON strings", async () => {
-    const op: Operation = {
-      id: "createVideos",
-      method: "POST",
-      path: "/videos",
-      summary: "Create video",
-      description: "",
-      params: [
-        { name: "name", in: "body", type: "string", required: true, description: "" },
-        { name: "content", in: "body", type: "object", required: true, description: "" },
-      ],
-      bodyRequired: true,
-      security: [],
-    };
-
-    let capturedBody: unknown;
-    vi.stubGlobal("fetch", vi.fn().mockImplementation((_url: string, init: RequestInit) => {
-      capturedBody = JSON.parse(init.body as string);
-      return Promise.resolve({
-        status: 200,
-        statusText: "OK",
-        headers: new Map([["content-type", "application/json"]]),
-        text: () => Promise.resolve("{}"),
-      });
-    }));
-
-    const spec = await loadSpec(FIXTURE);
-    const program = new Command();
-    program.exitOverride();
-    buildCommands(program, [{ tag: "Videos", description: "", operations: [op] }], config, spec);
-
-    await program.parseAsync(["node", "test", "Videos", "create", "--name", "Test", "--content", '{"text":"hello"}']);
-
-    expect(capturedBody).toEqual({ name: "Test", content: { text: "hello" } });
-
-    vi.unstubAllGlobals();
-  });
-
-  it("parses array params from JSON strings", async () => {
-    const op: Operation = {
-      id: "createItem",
-      method: "POST",
-      path: "/items",
-      summary: "Create items",
-      description: "",
-      params: [
-        { name: "tags", in: "body", type: "array", required: true, description: "" },
-      ],
-      bodyRequired: true,
-      security: [],
-    };
-
-    let capturedBody: unknown;
-    vi.stubGlobal("fetch", vi.fn().mockImplementation((_url: string, init: RequestInit) => {
-      capturedBody = JSON.parse(init.body as string);
-      return Promise.resolve({
-        status: 200,
-        statusText: "OK",
-        headers: new Map([["content-type", "application/json"]]),
-        text: () => Promise.resolve("{}"),
-      });
-    }));
-
-    const spec = await loadSpec(FIXTURE);
-    const program = new Command();
-    program.exitOverride();
-    buildCommands(program, [{ tag: "Items", description: "", operations: [op] }], config, spec);
-
-    await program.parseAsync(["node", "test", "Items", "create", "--tags", '["a","b"]']);
-
-    expect(capturedBody).toEqual({ tags: ["a", "b"] });
-
-    vi.unstubAllGlobals();
-  });
-
-  it("falls back to string when JSON parse fails", async () => {
-    const op: Operation = {
-      id: "createThings",
-      method: "POST",
-      path: "/things",
-      summary: "Create thing",
-      description: "",
-      params: [
-        { name: "data", in: "body", type: "object", required: true, description: "" },
-      ],
-      bodyRequired: true,
-      security: [],
-    };
-
-    let capturedBody: unknown;
-    vi.stubGlobal("fetch", vi.fn().mockImplementation((_url: string, init: RequestInit) => {
-      capturedBody = JSON.parse(init.body as string);
-      return Promise.resolve({
-        status: 200,
-        statusText: "OK",
-        headers: new Map([["content-type", "application/json"]]),
-        text: () => Promise.resolve("{}"),
-      });
-    }));
-
-    const spec = await loadSpec(FIXTURE);
-    const program = new Command();
-    program.exitOverride();
-    buildCommands(program, [{ tag: "Things", description: "", operations: [op] }], config, spec);
-
-    await program.parseAsync(["node", "test", "Things", "create", "--data", "not-json"]);
-
-    expect(capturedBody).toEqual({ data: "not-json" });
-
-    vi.unstubAllGlobals();
-  });
-});
diff --git a/src/executor/commander-builder.ts b/src/executor/commander-builder.ts
index cc539f6..01d1ea1 100644
--- a/src/executor/commander-builder.ts
+++ b/src/executor/commander-builder.ts
@@ -2,6 +2,7 @@ import { Command } from "commander";
 import type { OperationGroup, Operation, OpenAPISpec } from "../parser/types.js";
 import type { RuntimeConfig } from "./types.js";
 import { executeRequest } from "./http.js";
+import { sanitizeCommandName, uniqueName } from "../cli/sanitize.js";
 
 export function buildCommands(
   program: Command,
@@ -9,9 +10,11 @@ export function buildCommands(
   config: RuntimeConfig,
   spec: OpenAPISpec
 ): void {
+  const usedNames = new Set<string>();
   for (const group of groups) {
+    const groupName = uniqueName(sanitizeCommandName(group.tag), usedNames);
     const groupCmd = program
-      .command(group.tag)
+      .command(groupName)
       .description(group.description);
 
     for (const op of group.operations) {
@@ -128,3 +131,4 @@ function simplifyName(operationId: string, tag: string): string {
 
   return operationId.toLowerCase();
 }
+