# Document an Axum Module with a README in 2026

> Atlas helps Axum developers in 2026 produce accurate, traceable README documentation by reading live code and verifying samples with `bash`.

Atlas empowers Axum developers in 2026 to generate precise README documentation directly from their codebase, ensuring that what's written reflects the current implementation, not historical intent. By leveraging tools like `lsp` for API enumeration, `read` for source analysis, and `bash` for sample verification, Atlas produces traceable documentation. This process integrates direct with your existing Axum toolchain, including `cargo` for package management, `cargo nextest` for robust testing, and `rustfmt` for consistent code formatting, providing a practical option for maintaining up-to-date module documentation that truly describes what the code does today.

## Key takeaways

- Atlas generates Axum READMEs directly from live code, ensuring accuracy and traceability.
- The `lsp` tool guarantees all public Axum APIs are enumerated and documented.
- `codebase_search` identifies real Axum usage patterns for practical code examples.
- Every Axum code sample in the generated README is verified by `bash` execution.
- Atlas integrates direct with `cargo`, `cargo nextest`, and `rustfmt` for Axum development.
- All Axum documentation changes require explicit user approval via a unified diff.

## How Atlas Documents Axum Module APIs Accurately

In 2026, Atlas ensures comprehensive documentation for Axum modules by first enumerating the public API surface using the `lsp` tool's `documentSymbol` operation. This guarantees that every exported function, struct, or trait in your Axum crate is identified, preventing any omissions or invented interfaces in the generated README.

Atlas begins the documentation process for an Axum module by leveraging its `lsp` tool. Specifically, the `documentSymbol` operation provides a precise, machine-readable list of all public API elements exported by your Axum crate. This is crucial for Axum applications, where handlers are plain async functions and the `Router` defines the public surface. By relying on the Language Server Protocol, Atlas avoids making assumptions or missing any part of the module's external interface. This ensures that the generated README accurately reflects the module's current public contract, including all `Router` routes, `State` types, and custom `Extractor`s, rather than what might have been planned a year ago. The output from `lsp` forms the foundational blueprint for the README, guaranteeing that every claim about the API is directly traceable to the live Axum source code.

## Analyzing Axum Handler Behavior and Usage Patterns

To accurately describe an Axum module's behavior in 2026, Atlas employs its `read` tool to analyze the implementation of each public export. Furthermore, `codebase_search` identifies how these Axum handlers and types are actually used across the repository, providing concrete examples for the README, ensuring 100% accuracy.

After enumerating the public API, Atlas delves into the actual implementation of each Axum handler and type. The `read` tool processes the source code, understanding the logic and data flow within your Axum module. For instance, it can analyze how a specific handler function in `src/handlers/user_handlers.rs` processes requests or how a custom `tower` layer modifies the request-response cycle. To provide real-world context, Atlas then uses `codebase_search` to find practical examples of how these APIs are invoked by other parts of your Axum application. This might involve finding calls to `Router::route` or instances where a particular `State` type is used. This dual approach ensures that the documentation not only describes what an Axum component does but also illustrates how it is used in practice, making the README highly relevant and actionable for other developers.

## Generating and Verifying Axum READMEs with Real Code

Atlas generates Axum module READMEs in 2026 by first using `grep` to find existing READMEs, ensuring the new documentation matches established project tone and structure. The `write` tool then crafts the README, quoting real Axum signatures and file paths, with every code sample verified by `bash` for 0 errors.

When it is time to generate the README for an Axum module, Atlas first uses its `grep` tool to scan the repository for existing documentation files, such as `docs/modules/existing_module/README.md`. This step is critical for maintaining consistency in heading structure, tone, and overall style across your project's documentation. Once the stylistic guidelines are understood, the `write` tool constructs the new README. This documentation includes real Axum code signatures, actual file paths like `src/main.rs` or `Cargo.toml`, and concrete examples derived from the `read` and `codebase_search` steps. Crucially, every single code sample embedded in the README is then executed by the `bash` tool. This verification step ensures that all Axum code snippets are functional, compile correctly, and produce the expected output, eliminating the liability of outdated or broken examples that often plague manual documentation efforts.

## Ensuring Safety and Review for Axum Code Changes

Atlas prioritizes safety in 2026 by permission-gating every tool call against `allow`, `ask`, and `deny` rules before execution, especially for actions like running `cargo nextest run`. All proposed file edits, including README updates, are presented as a unified diff for explicit approval before Atlas writes them to disk, typically within 1-2 seconds.

Safety and developer control are paramount when Atlas interacts with your Axum codebase. Before any tool, such as `cargo nextest` for running tests or `rustfmt` for formatting, is executed, Atlas consults its permission-gating system. This system allows you to configure `allow`, `ask`, or `deny` rules for specific operations, ensuring that Atlas only performs actions you explicitly permit. For instance, running `cargo nextest run` to verify an Axum application's tests will always be behind a permission prompt. Furthermore, Atlas drafts its plan in a read-only agent and, once a plan is approved, switches to a build agent. Any proposed changes, including the new or updated README file, are presented as a unified diff. This allows you to review every line Atlas intends to write to your Axum project, providing a final layer of approval before the changes are committed, ensuring full transparency and control over your documentation and code.

## Steps

1. Run Atlas in your Axum crate's root directory: `atlas`
2. Enumerate the Axum module's public API using `lsp`: `atlas lsp documentSymbol src/lib.rs` (or `src/main.rs`)
3. Read implementation details and find usage patterns: `atlas read src/my_axum_module/mod.rs` and `atlas codebase_search "my_axum_handler"`
4. Grep for existing READMEs to match style and tone: `atlas grep "## Usage" docs/README.md`
5. Draft the new or updated README with the `write` tool: `atlas write docs/modules/my_axum_module/README.md`
6. Verify all code samples in the README by executing them with `bash`: `atlas bash "cargo run --example my_axum_app"`
7. Review the unified diff of the proposed README changes and approve them.
8. Optionally, have Atlas run tests and format the code: `atlas ask "cargo nextest run"` and `atlas ask "rustfmt src/my_axum_module/mod.rs"`

## FAQ

### How does Atlas ensure Axum documentation is up-to-date?

Atlas uses its `lsp` tool to enumerate the current public API of your Axum module and `read` to analyze the actual implementation. This ensures the documentation reflects the code as it exists today, not outdated specifications or intentions from a year ago.

### Can Atlas document Axum handlers that use custom `Extractor`s or `State`?

Yes, Atlas is designed to read your Axum `Router`, the `State` type you thread through handlers, and every `tower` layer in the stack. It can even help decode trait-bound errors you might encounter with custom `Extractor`s.

### How does Atlas verify code examples in an Axum README?

Atlas uses the `bash` tool to execute every code sample it includes in the generated README. This critical step ensures that all Axum code snippets are functional, compile correctly, and produce the expected output, preventing broken examples.

### What Axum-specific tools does Atlas integrate with?

Atlas integrates directly with the standard Axum toolchain, including `cargo` for package management, `cargo nextest` for running tests, and `rustfmt` for consistent code formatting, providing a familiar and efficient development experience.

### Is it safe to let Atlas modify my Axum codebase?

Yes, Atlas operates with a strong emphasis on safety. Every tool call is permission-gated against `allow`, `ask`, and `deny` rules. All proposed file edits, including README updates, are presented as a unified diff for your explicit approval before being written to your Axum project.

### How does Atlas handle the style and tone of an existing Axum project's READMEs?

Before writing a new README, Atlas uses its `grep` tool to search the repository for existing READMEs. This allows it to match the established heading structure, tone, and overall style, ensuring consistency within your Axum project's documentation.

### Can Atlas help fix common Axum development issues during documentation?

While primarily a documentation agent, Atlas can assist with related issues. For instance, it can help decode trait-bound errors when an Axum handler argument is not an `Extractor` or suggest adding a custom `IntoResponse` error type so handlers stop returning bare status codes.

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Canonical HTML: https://runatlas.sh/resources/stacks/document-a-module-with-a-readme-in-axum
Source of truth: aeo_pages row `/resources/stacks/document-a-module-with-a-readme-in-axum` (segment: Stacks) (this file is generated from it, never hand-edited).
Licence: Atlas is proprietary with a free core. It is not open source and there is no public source repository.