Quick start guide for the Tessl Framework

Install Tessl

Follow the Installation steps. Be sure to login. You can verify Tessl is installed by typing tessl on the command line, and that you're logged in by typing tessl whoami. Once you've done this, create a new directory for your project and navigate to it. We'll use quickstart for this example, and will refer to it as the root directory.

Initialize Tessl in your project

Next, run the following command to set up tessl in your project.

tessl init

This will add configuration files (which you can read more about on the Configuration page). You will then be prompted on how you wish to use Tessl. You can select to use the Tessl Framework for spec driven development and the Spec Registry, or just the Spec Registry. Choose to use Tessl Framework:

Afterward, you will also be prompted to setup an agent, this is optional, but strongly recommended. Tessl performs best in conjuction with an AI agent, although you can also use Tessl via the CLI. See step 3 for more information on agent setup.

Set up agent integration (recommended)

If you had previously skipped setting up Tessl with your preferred agent, run the following command:

tessl setup agent

Both the tessl init and tessl setup agent commands result in asking if you want to automatically configure the MCP server for your preferred agent. This step is optional, but recommended for the best experience using Tessl.

Choose to auto-configure, when prompted.

Your agent would be able to connect to Tessl via MCP once initiatlized.

If your agent isn't listed, or if your agent doesn't pick up the server when initialized, you may need to configure the MCP server manually. Refer to your agent's documentation for precise instructions but in most cases the configuration should look something like this:

{
  "tessl": {
    "type": "stdio",
    "command": "tessl",
    "args": ["mcp"]
  }
}

Create your first spec

Now that you've initialized Tessl, let's use it to create a spec that pluralizes a given English word.

We'll use Claude Code as our agent in our examples going forward. You can run the same prompts in your agent of choice. Alternatively, you can also use the Tessl CLI directly, as shown in the second tab.

If using MCP, the agent will ask questions about your project to capture relevant information in AGENTS.md. This context will be used in code generation and we encourage you to add any useful details about your intended project set up such file. If you're using the Tessl CLI, you'll need to run tessl setup project-info first which will interview you about your requirements and the context to be added to AGENTS.md for you.

Agent

Tessl CLI

After starting Claude Code, provide the following prompt

Copy

Write a spec that pluralizes English words.  Use <your preferred language> 

Respond to the interview questions or ask the agent to choose. For example, when asked about language, framework, and directory structure, you can choose to use the suggested language, test framework and directory structure

Similarly, if asked about features you may choose to use the basic ones just to start and build out over time. When in doubt, tell the agent to decide.

A spec will be generated.

As the flow progresses it may ask you to build it, you may proceed or decide to tell Claude Code not to, so you can jump immediately into reviewing and updating the spec in the next step.

Review the spec

You have just generated your first spec file with Tessl. Review what has been generated. You'll find the spec in the specs directory found in your root directory (if that's the location you chose in the initial project setup). For more information about Tessl specs, refer to the Specs page.

You can manually change the generated spec for minor changes or use the following steps for any edits.

Agent

Tessl CLI

Copy

Edit the Tessl spec to add a new capability for plurals that are exception words.

Build the implementation

Once you're happy with the content of your spec, generate the implementation code.

Remember that generation will use any context in AGENTS.md and files linked from it so update these files with any particular project requirements you have such as code style.

Agent

Tessl CLI

Copy

build my application

You may be prompted to generate tests. Select yes to validate your functionality.

Run your generated code

Take your new application for a spin! Ask your agent how to run it if you're unsure.

Next steps

Iterate to add functionality to your application and make it more robust by adding tests and documentation to your project.