gamma-local-dev-loop

Set up local development workflow for Gamma API integration. Use when building automation scripts, testing API calls locally, or configuring a dev environment with mock responses. Trigger: "gamma local dev", "gamma development setup", "gamma test locally", "gamma mock API", "gamma dev workflow".

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Repository: jeremylongshore/tons-of-skills-marketplace
Last source activity: August 19, 2026 at 12:13
Detected SKILL.md language: English
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name	gamma-local-dev-loop
description	Set up local development workflow for Gamma API integration. Use when building automation scripts, testing API calls locally, or configuring a dev environment with mock responses. Trigger: "gamma local dev", "gamma development setup", "gamma test locally", "gamma mock API", "gamma dev workflow".
allowed-tools	Read, Write, Edit, Bash(curl:), Bash(node:), Bash(npm:*)
version	1.13.0
license	MIT
author	Jeremy Longshore <jeremy@intentsolutions.io>
tags	["saas","gamma","development","testing"]
compatibility	Designed for Claude Code

Gamma Local Dev Loop

Overview

Set up an efficient local development workflow for Gamma API integrations. Since Gamma is a REST API with no SDK, the dev loop centers on HTTP request/response testing, mock servers for offline development, and a reusable client wrapper.

Prerequisites

Completed gamma-install-auth setup
Node.js 18+ with tsx for TypeScript execution
GAMMA_API_KEY in .env

Instructions

Step 1: Project Structure

gamma-integration/
├── src/
│   ├── client.ts          # Reusable Gamma API client
│   ├── generate.ts        # Generation workflows
│   └── poll.ts            # Polling helper
├── test/
│   ├── mock-server.ts     # Local mock for offline dev
│   └── integration.test.ts
├── .env                   # GAMMA_API_KEY (gitignored)
├── .env.example           # Template without secrets
├── package.json
└── tsconfig.json

Step 2: Reusable Client Wrapper

// src/client.ts
import "dotenv/config";

const GAMMA_BASE = "https://public-api.gamma.app/v1.0";

export interface GammaClient {
  generate(body: GenerateRequest): Promise<GenerateResponse>;
  poll(generationId: string): Promise<PollResponse>;
  listThemes(): Promise<Theme[]>;
  listFolders(): Promise<Folder[]>;
}

export function createClient(apiKey?: , ?: ):  {
   key = apiKey ?? process..;
   (!key)   ();
   base = baseUrl ?? ;
   headers = { : key, :  };

    () {
     res =  (, {
      method,
      headers,
      : body ? .(body) : ,
    });
     (!res.) {
       text =  res.();
        ();
    }
     res.();
  }

   {
    :  (, , body),
    :  (, ),
    :  (, ),
    :  (, ),
  };
}

// src/poll.ts
import type { GammaClient } from "./client";

export async function waitForCompletion(
  client: GammaClient,
  generationId: string,
  opts = { intervalMs: 5000, timeoutMs: 120000 }
) {
  const deadline = Date.now() + opts.timeoutMs;
  while (Date.now() < deadline) {
    const result = await client.poll(generationId);
    if (result.status === "completed") return result;
    if (result.status === "failed") throw new Error(`Generation failed: ${result.error}`);
    await new Promise((r) => setTimeout(r, opts.intervalMs));
  }
  throw new Error(`Poll timeout after ${opts.timeoutMs}ms`);
}

// test/mock-server.ts
import http from "node:http";

const MOCK_PORT = 9876;
const generations = new Map<string, { status: string; tick: number }>();

const server = http.createServer((req, res) => {
  res.setHeader("Content-Type", "application/json");

  // POST /v1.0/generations
  if (req.method === "POST" && req.url === "/v1.0/generations") {
    const id = `mock_${Date.now()}`;
    generations.set(id, { status: "in_progress", tick: 0 });
    res.end(JSON.stringify({ generationId: id }));
    return;
  }

  // GET /v1.0/generations/:id — completes after 3 polls
  const pollMatch = req.url?.match(/\/v1\.0\/generations\/(.+)/);
  if (req.method === "GET" && pollMatch) {
    const gen = generations.get(pollMatch[1]);
    if (!gen) { res.writeHead(404); res.end("{}"); return; }
    gen.tick++;
    if (gen.tick >= 3) gen.status = "completed";
    res.end(JSON.stringify({
      generationId: pollMatch[1],
      status: gen.status,
      ...(gen.status === "completed" && {
        gammaUrl: `https://gamma.app/docs/mock-${pollMatch[1]}`,
        exportUrl: `https://export.gamma.app/mock.pdf`,
        creditsUsed: 10,
      }),
    }));
    return;
  }

  // GET /v1.0/themes
  if (req.url === "/v1.0/themes") {
    res.end(JSON.stringify([
      { id: "theme_1", name: "Professional" },
      { id: "theme_2", name: "Modern" },
    ]));
    return;
  }

  // GET /v1.0/folders
  if (req.url === "/v1.0/folders") {
    res.end(JSON.stringify([{ id: "folder_1", name: "Test Folder" }]));
    return;
  }

  res.writeHead(404);
  res.end("{}");
});

server.listen(MOCK_PORT, () => console.log(`Mock Gamma API on :${MOCK_PORT}`));

{
  "scripts": {
    "dev:mock": "tsx test/mock-server.ts",
    "dev:generate": "tsx src/generate.ts",
    "test": "vitest run",
    "test:integration": "GAMMA_BASE=http://localhost:9876/v1.0 vitest run test/integration"
  }
}

// test/integration.test.ts
import { describe, it, expect } from "vitest";
import { createClient } from "../src/client";
import { waitForCompletion } from "../src/poll";

const BASE = process.env.GAMMA_BASE ?? "http://localhost:9876/v1.0";

describe("Gamma API", () => {
  const client = createClient("test-key", BASE);

  it("generates and polls to completion", async () => {
    const { generationId } = await client.generate({
      content: "Test presentation",
      outputFormat: "presentation",
    });
    expect(generationId).toBeTruthy();

    const result = await waitForCompletion(client, generationId);
    expect(result.status).toBe("completed");
    expect(result.gammaUrl).toContain("gamma.app");
  });

  it("lists workspace themes", async () => {
    const themes = await client.listThemes();
    expect(themes.length).toBeGreaterThan(0);
  });
});

Activity	Command	Hits Live API?
Start mock server	`npm run dev:mock`	No
Generate (mock)	`GAMMA_BASE=http://localhost:9876/v1.0 npm run dev:generate`	No
Run tests	`npm test` (uses mock)	No
Live API test	`GAMMA_API_KEY=gma_... tsx src/generate.ts`	Yes

Issue	Cause	Fix
`GAMMA_API_KEY required`	Missing env var	Add to `.env` or export
Mock returns 404	Wrong mock port/path	Verify `GAMMA_BASE` points to mock
Poll timeout locally	Mock tick count too high	Reduce tick threshold
`fetch is not defined`	Node.js < 18	Upgrade to Node.js 18+