New: We just launched Vespper DOCX MCP: 3× faster, 2× cheaper, and more accurate. Click here

Y CombinatorBacked by Y Combinator

Let your agent edit Word documents while maintaining styling & formatting.

Start now
import Vespper from "vespper";
import { createMCPClient } from "@ai-sdk/mcp";
import { generateText } from "ai";

const client = new Vespper();
const sessionId = await client.openSession("./nda.docx");

const mcp = await createMCPClient({
  transport: {
    url: "https://mcp.vespper.com/mcp",
    headers: { Authorization: client.authorizationHeader },
  },
});
await client.patchMCPTools({ mcp, sessionId });

await generateText({
  model: "openai/gpt-5.6-sol",
  tools: await mcp.tools(),
  prompt: "Fill this NDA with the data from the .csv file",
});

Made by professionals from

Viz.ai
Google
Y Combinator
Snyk

3x faster, 2x cheaper, more accurate

Better, cheaper & faster.

Vespper is 2.7–2.9× cheaper and 2.7–3.5× faster than the DOCX skill, while being more accurate.

Cost per task9/1/2026
  1. 1Vespper DOCX$0.054
  2. 2DOCX Skill$0.157
  3. 3Office CLI MCP$0.240
Task accuracy9/1/2026
  1. 1Vespper DOCX81.4%
  2. 2DOCX Skill78.1%
  3. 3Office CLI MCP65.2%
Median latency9/1/2026
  1. 1Vespper DOCX14.6s
  2. 2DOCX Skill51.5s
  3. 3Office CLI MCP57.1s

Across all 10 matched comparisons, five alternatives × two models, the median competitor costs 2.43× as much, while Vespper costs 58.9% less. Vespper is 16.2 percentage points more accurate and 1.97× faster, with 47.7% lower latency making it the best option for agents to edit .docx files.

Vespper v1.0 benchmark results using GPT-5.6 Sol. Cards compare the same task against the DOCX Skill and Office CLI MCP. Read the full benchmark methodology or compare Vespper with the DOCX skill.

Kickstart your next project with these open-source templates.

Example

Word add-in

A complete Office add-in that brings agentic document editing directly into Microsoft Word.

Example

ONLYOFFICE plugin

A chat plugin for ONLYOFFICE Docs that proposes AI edits as suggestion cards to review and apply.

Example

EigenPal's docx-editor

A browser app with a chat beside EigenPal's docx-editor, where AI edits appear as suggestions or tracked changes.

View all examples

Frequently asked questions

Vespper security program status
Why Vespper?

Vespper gives AI agents three tools to read, search and edit Microsoft Word documents. Agents work with HTML while Vespper applies edits to the original DOCX, preserving styles and formatting and recording edits as Word tracked changes.

Is Vespper SOC 2 compliant?

Vespper's SOC 2 program is in progress. Contact us at founders@vespper.com to review the current security documentation and discuss your requirements.

Do you offer a skill instead of MCP?

A standalone skill is coming soon. For now, connect your agent through our MCP server. Email founders@vespper.com if you're interested in the skill.

Can I self-host Vespper models?

Self-hosting is available as an enterprise option. Contact founders@vespper.com to discuss the deployment, security and support requirements for your environment.

How does Vespper handle sensitive documents?

Enterprise plans can include zero-data-retention deployment and self-hosting. Data handling and retention controls are scoped and documented for each customer. Contact founders@vespper.com to confirm the controls available for your deployment.

How quickly can I get started?

You can start experimenting within minutes using our hosted MCP. For enterprise and self-hosted setups, our team provides guided onboarding to help you deploy Vespper quickly and securely in your stack.

Join the community

Share what you're building, ask questions, and see how other teams use Vespper with their agents.

Join us on Slack