# Document a module with a README in Expo with Atlas in 2026

> Atlas ensures Expo module documentation is always current by directly analyzing source code with tools like lsp and read, providing traceable and accurate READMEs.

Atlas helps Expo developers produce accurate, up-to-date documentation for modules by directly reading the codebase in 2026. It leverages tools like lsp to enumerate public APIs, read to understand implementation details, and codebase_search to find real-world usage, ensuring the generated README reflects the code's actual behavior today, not its historical intent. This process integrates direct with Expo's toolchain, including npx expo install and prettier.

## Key takeaways

- Atlas documents Expo modules by analyzing current code, not outdated specifications, ensuring accuracy in 2026.
- Real Expo toolchain commands like `npx expo install` and `prettier` are integrated into Atlas workflows.
- Atlas uses `lsp` to accurately map Expo module APIs and `codebase_search` for real-world usage patterns.
- Every generated code sample in Expo documentation is `bash` verified for functionality and correctness.
- Developers maintain full control with Atlas's permission-gated tools and diff review for Expo projects.

## How does Atlas document Expo module APIs in 2026?

Atlas documents Expo module APIs by using the lsp tool's documentSymbol operation to enumerate every public export, ensuring 100% coverage of the module's surface. This method guarantees that no function, class, or constant is missed or invented, providing a complete and accurate API reference for developers in 2026.

To create documentation that precisely describes what an Expo module's code actually does today, Atlas employs its lsp tool. Specifically, the documentSymbol operation is used to scan the module's source files, such as those within the `app/` directory, and identify all exported symbols. This includes functions, classes, variables, and any other public interfaces. By relying on the live code's Abstract Syntax Tree (AST) declarations, Atlas ensures that the documented API surface is exactly what is exposed by the module, rather than relying on outdated comments or assumptions. This approach is crucial for Expo projects where `expo-router` file routes and config plugins define much of the application's structure, ensuring that the documentation accurately reflects the current public interface available to other parts of the application or external consumers.

## How does Atlas understand real-world usage of Expo modules?

To ensure documentation reflects actual usage, Atlas employs the read tool to analyze the implementation of each export and codebase_search to find how callers use it in practice across the Expo project. This dual approach provides a comprehensive view, preventing documentation from becoming outdated or misaligned with 2026 development patterns.

Understanding how a module is actually used is as important as knowing its public API. Atlas achieves this by first using the read tool to delve into the implementation details of each identified export. This provides context on the function's logic, parameters, and return values. Following this, Atlas leverages codebase_search to scan the entire Expo project for instances where these exports are called or referenced. This search reveals real-world usage patterns, common arguments passed, and typical integration points within the application. For an Expo developer, this means the generated README will include practical examples and insights derived directly from their own codebase, reflecting how their `expo-router` routes or custom components interact with the module, ensuring the documentation is immediately relevant and useful for their specific project in 2026.

## How does Atlas generate a README for an Expo module?

Atlas generates a README for an Expo module by first using grep to find existing README.md files within the project, matching their heading structure and tone rather than inventing a new format. This ensures consistency across your 2026 documentation, then the write tool emits the new README, incorporating real signatures and file paths.

for generating the README, Atlas prioritizes consistency and accuracy. Before writing new content, Atlas uses the grep tool to search the repository for any existing `README.md` files. This step allows Atlas to analyze the established heading structure, formatting conventions, and overall tone, ensuring that the new documentation direct integrates with the project's existing style. Once the structure is determined, the write tool is employed to construct the README. This includes quoting real function signatures and referencing actual file paths from the Expo project, such as `app/components/MyModule.tsx` or configurations in `app.config.ts`. By sourcing all information directly from the codebase and adhering to existing documentation styles, Atlas produces a README that is both accurate and familiar to the Expo developer in 2026, making it easier to maintain and understand.

## How does Atlas verify code samples in Expo documentation?

Atlas verifies every code sample within the generated documentation by running it with the bash tool, ensuring that a sample that was never executed does not become a liability for Expo developers. This critical step confirms that all examples are functional and accurate in 2026, preventing broken code snippets from reaching your users.

A code sample that does not run is worse than no code sample at all. Atlas addresses this by rigorously verifying every code snippet included in the generated documentation. Using the bash tool, Atlas executes each code sample in a controlled environment. This process catches syntax errors, incorrect API usage, and missing dependencies, ensuring that the examples are truly runnable. For Expo projects, this might involve ensuring that `npx expo install` commands for dependencies are correct, or that a component example can be rendered without errors. This proactive verification step guarantees that any developer copying a code sample from the README in 2026 will find working, reliable code, significantly reducing frustration and improving the quality of the documentation.

## How does Atlas ensure safety and review for Expo developers?

Atlas prioritizes safety and developer control, especially when generating documentation for Expo projects in 2026. Every Atlas tool call is permission-gated against allow, ask, and deny rules before it runs, and Atlas drafts a plan in a read-only plan agent, asking for approval before switching to a build agent to make changes.

Developer control and safety are paramount when using an AI coding agent like Atlas. For Expo developers, Atlas implements several layers of protection. Firstly, every tool call, whether it's `lsp`, `read`, `grep`, `write`, or `bash`, is permission-gated. This means you explicitly allow, ask for confirmation, or deny Atlas from executing specific operations. Secondly, Atlas operates with a clear separation between planning and execution. It first drafts a comprehensive plan in a read-only plan agent, detailing the steps it intends to take to document your Expo module. You review and approve this plan before Atlas switches to a build agent to make any actual changes. Finally, before writing any modifications to your `README.md` or other files, Atlas computes a unified diff, which is presented for your final approval. Atlas also snapshots file changes as git patches, allowing for easy rollback if needed. This robust review process ensures that you, the Expo developer, maintain full oversight and control over your codebase in 2026.

## Steps

1. Run Atlas in your Expo project, ensuring an `app.json` or `app.config.ts` and an `app/` directory are present.
2. Allow Atlas to read your `expo-router` routes, the `plugins` array in your config, and `eas.json` build profiles to understand project context.
3. Instruct Atlas to enumerate the module's public API using the `lsp` tool's `documentSymbol` operation, capturing all exports.
4. Permit Atlas to `read` the implementation of each export and use `codebase_search` to find how callers actually use it within your Expo codebase.
5. Grant Atlas permission to `grep` your repository for an existing `README.md` to match its heading structure and tone.
6. Approve Atlas to `write` the new `README.md` with real signatures and file paths, based on its analysis.
7. Allow Atlas to `bash` verify every code sample in the generated documentation, ensuring all examples are runnable and accurate.
8. Review the unified diff presented by Atlas for the new `README.md` and approve the changes before they are written to your Expo project.

## FAQ

### How does Atlas ensure Expo documentation is up-to-date in 2026?

Atlas directly reads your Expo project's source code using tools like `lsp` and `read` to generate documentation. This process ensures the README reflects the code's current state, not its historical intent, providing accurate information for 2026 development.

### Can Atlas document `expo-router` routes or config plugins?

Yes, Atlas is designed for Expo apps. It reads `expo-router` file routes and the `plugins` array in your `app.json` or `app.config.ts` to understand your project's structure and document relevant components and configurations.

### What Expo tools does Atlas integrate with for documentation?

Atlas integrates with core Expo tools. It can install packages using `npx expo install`, run tests with `jest-expo` behind a permission prompt, and format generated documentation diffs with `prettier` before writing.

### How does Atlas handle code samples in Expo READMEs?

Atlas verifies every code sample it includes in an Expo README by executing it with the `bash` tool. This ensures that all examples are functional and accurate, preventing broken or misleading code snippets from being published.

### Is it safe to let Atlas modify my Expo project files?

Yes, Atlas is designed with safety in mind. It operates with permission-gated tool calls, drafts plans in a read-only agent, and presents a unified diff for every file edit. You must approve all changes before Atlas writes them to your Expo project.

### Does Atlas use local embeddings for Expo code?

Yes, Atlas can build its code index with local Ollama embeddings. This capability keeps your Expo project's code off third-party servers, enhancing privacy and security for your development environment.

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Canonical HTML: https://runatlas.sh/resources/stacks/document-a-module-with-a-readme-in-expo
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Licence: Atlas is proprietary with a free core. It is not open source and there is no public source repository.