Last week, the Anthropic team launched its new plugins marketplace experience. Plugins isn’t a new concept for Claude. This release serves as a better way for builders to submit them into the marketplace. I’m thrilled about Anthropic’s recent investment in the plugins infrastructure. Carta has been an early adopter, launching our plugins suite back in April. Since then, we’ve been building at the frontier of what’s possible in service of a better experience for our users. Let me explain.
Carta was probably one of the earliest company-wide rollouts of Claude Desktop. As soon as we got our hands on this experience, we made a bet that the future of work will happen through a centralized agent harness. If LLMs are the new word-chip, then the harness is the operating system. We went all in on building for this new world. Most SaaS builders at the time built MCP. Carta, in the spirit of opinionated and intentional experiences, went all in on plugins.
MCP vs. plugin
MCP is what the industry has converged on as a standard way for LLMs to connect to an application, pulling in its data and taking actions within it. It’s the API for LLMs. Plugins, on the other hand, package the skills, tools, and rich experiences that guide the agent in how to use one or more MCP connections.
To draw an analogy, think of MCP as the electrical outlet in your wall. It's the universal standard that lets any device plug in and get power. It's great because it's open and works everywhere, but an outlet by itself doesn't do anything for you. You still need an appliance.
A plugin is the appliance. It plugs into that same outlet (MCP), but it also comes with everything needed to actually get work done: the know-how for a specific job, shortcuts, and automation, all packaged together. Instead of asking someone to wire up their own connection and then figure out how to use it, we hand them a finished product they can install in one click and start using immediately.
Why this matters
For customers, it means less setup and less guesswork. They don’t have to “prompt engineer” to get the right outputs from Carta’s MCP. Our plugins help create consistency, accuracy, and a much better customer experience. This might come in the form of a deterministic SQL script, a beautifully designed artifact or even a micro-app.
When I run into customers who are AI skeptics, it is usually because they have run into cases where AI produces incorrect or inconsistent outputs. Remember that LLMs are probabilistic word calculators. Consistency and accuracy are not their strengths. But our plugins change that.
What plugins have unlocked
The Carta suite of plugins—Cap Table, Investors, and CRM—have packaged dozens of skills, artifacts, and now our first set of micro-apps. Here are some of my favorites.
Carta Home
The Cap Table and Investors plugin both have a Home artifact. We encourage customers to load the artifact and pin it for easy access. Carta Home serves as a dashboard for Carta users on Claude Desktop. It shows relevant data, suggested prompts based on usage, a skills directory, and the latest plugin news and events.
Valuations and waterfall modeling for Excel
This is one of our most heavily used skills. Packaging deterministic software scripts into a plugin enables "hard math," and this is why it matters. It also allows us to meet our users where they are already doing this work. This skill grabs the source of truth data from Carta, runs locally downloaded scripts to run valuations and waterfalls, and outputs the results directly into Excel.
Fund modeling micro-app
We have so much to say about micro-apps that it is fitting for another post. The fund modeling micro-app is a full-featured multi-page experience that talks to the MCP but has locally embedded logic. The strategic planning of a fund is its IP. We know customers want to endlessly tailor this experience for their needs. It was an obvious use case for a micro-app.
These skills and artifacts, when packaged in a plugin, are customizable. They serve as starting points for clients to prompt Claude to tailor and customize for their needs.
Tradeoffs
There are tradeoffs to this approach. Plugins are not very portable across the different harnesses, Codex, Cursor, etc. We’ll have to build specific experiences for each of these harnesses. This is why most SaaS builders have only built MCPs.
But publishing an unopinionated API was never a viable path for us. We are building financial applications for CFOs, founders, GPs, and LPs. Trust, accuracy and consistency are non-negotiables. Delivering a beautiful user experience and packaging our expertise is core to how we build. So for now, as we’ve always done, we go narrow and deep to give our clients the best of what is possible.
DISCLOSURE: This communication is on behalf of eShares, Inc. dba Carta, Inc. ("Carta"). This communication is for informational purposes only, and contains general information only. Carta is not, by means of this communication, rendering accounting, business, financial, investment, legal, tax, or other professional advice or services. This publication is not a substitute for such professional advice or services nor should it be used as a basis for any decision or action that may affect your business or interests. Before making any decision or taking any action that may affect your business or interests, you should consult a qualified professional advisor. This communication is not intended as a recommendation, offer or solicitation for the purchase or sale of any security. Carta does not assume any liability for reliance on the information provided herein. © 2026 Carta. All rights reserved. Reproduction prohibited.
