# Audit a Ruby on Rails Repository with Parallel Subagents in Atlas (2026)

> Atlas allows Ruby on Rails developers to audit large repositories efficiently by fanning out work to parallel subagents, preserving the main session's context window.

Atlas enables Ruby on Rails developers to sweep an entire repository for specific problems without exceeding the main session's context window by leveraging parallel subagents. This approach allows you to audit large Rails applications, inspecting models, controllers, and Active Record migrations, while still using familiar tools like `RSpec` for testing, `Bundler` for dependency management, and `RuboCop` for code formatting and linting.

## Key takeaways

- Atlas uses parallel subagents to audit large Ruby on Rails repositories without blowing the main context window.
- Subagents operate in isolated sessions, returning only conclusions, not raw file dumps.
- The `explore` subagent type is ideal for read-only sweeps of your Rails codebase.
- You can split audits by Rails directories like `app/models` or `app/controllers` for efficient parallel processing.
- Atlas integrates with Ruby on Rails tools like `RSpec`, `Bundler`, and `RuboCop` for comprehensive analysis.
- All changes proposed by Atlas are permission-gated and require explicit approval via unified diffs.

## How Atlas Audits Ruby on Rails Repositories with Parallel Subagents

Atlas audits Ruby on Rails repositories by splitting the workload into independent slices, launching multiple subagents concurrently to process each part. This method prevents the main session's context window from being overwhelmed, even when examining hundreds of files across your Rails application in 2026.

When auditing a Ruby on Rails application, Atlas uses its `task` tool to launch multiple subagents. Each subagent operates in its own isolated session, ensuring that its file dumps and intermediate thoughts do not consume the main agent's context window. Only the subagent's final conclusions are returned to the main session. For a read-only sweep, the `explore` subagent type is ideal, as it is deny-by-default, preventing any unintended modifications to your Rails codebase. This allows you to inspect `app/models`, `app/controllers`, `db/migrate`, and other critical Rails directories without risk.

## Splitting Your Ruby on Rails Audit into Manageable Slices

To effectively audit a Ruby on Rails repository, you must split the task into independent slices, ensuring subagents do not overlap their work. For example, you might assign one subagent to all `app/models` files and another to `app/controllers`, allowing 2 or more subagents to run in parallel.

The key to an efficient parallel audit in a Ruby on Rails project is to define distinct slices for each subagent. This can be done by directory, by specific Rails component (e.g., all `Active Record` models, all `RSpec` test files), or by a particular rule you are checking. For instance, one subagent could focus on `app/models/**/*.rb` to check for N+1 query issues, while another examines `app/controllers/**/*.rb` for security vulnerabilities. Atlas's `glob` tool can help define these file sets precisely, ensuring each subagent has a clear, non-overlapping scope within your Rails application structure.

## Launching Concurrent Subagents for Ruby on Rails Code Sweeps

Launching multiple subagents concurrently is crucial for speeding up repository audits in Ruby on Rails, allowing several parts of your codebase to be analyzed simultaneously. You can issue 3 or more `task` calls together, ensuring they run in parallel rather than sequentially, significantly reducing total audit time.

Atlas's `task` tool is used to launch subagents. To achieve concurrency, you issue multiple `task` calls in quick succession. For a read-only sweep of your Ruby on Rails project, you specify `subagent_type explore`. For example, you might launch one task to audit `app/models` and another for `app/views` at the same time. The `explore` subagent is configured to be read-only by default, making it safe for comprehensive audits where no changes should occur. If a subagent needs to run commands like `bundle exec rubocop` or `bundle exec rspec` to gather information, you would use `subagent_type general` instead, but always with careful permission gating.

## Reviewing and Merging Findings from Ruby on Rails Subagents

After subagents complete their sweeps of your Ruby on Rails codebase, Atlas collects their final messages, including any errors, for your review. This consolidation step allows you to merge findings from 5 or more parallel tasks into a single actionable `todowrite` list.

Once all subagents have finished their assigned tasks, Atlas automatically collects their final messages. If a subagent encounters an error, its error text is surfaced verbatim. If a task was cancelled, Atlas reports 'Task cancelled'. You then merge these individual findings into a unified `todowrite` list. This list serves as a consolidated action plan for addressing the identified issues within your Ruby on Rails application. For example, if multiple subagents found different `RuboCop` violations or potential `Active Record` performance bottlenecks, they would all be aggregated here. You can then use the `edit` tool in the main Atlas session to implement the necessary fixes, reviewing each change via a unified diff before committing.

## Ensuring Safety and Control in Ruby on Rails Audits with Atlas

Atlas provides robust safety mechanisms for auditing Ruby on Rails repositories, including permission-gated tool calls and a read-only plan agent. Every tool call, whether it's running `bundle exec rspec` or modifying a file, is checked against allow, ask, or deny rules, offering 100% control over agent actions.

Safety is paramount when auditing a Ruby on Rails codebase. Atlas ensures this through several layers of control. First, every tool call made by an agent is permission-gated, requiring explicit approval based on your configured allow, ask, or deny rules. Second, Atlas drafts a plan in a read-only plan agent and asks for your approval before switching to a build agent that can execute changes. Third, for any file edits, Atlas computes a unified diff and surfaces it for your approval before writing to disk. This means you always review proposed changes to your `config/application.rb`, `Gemfile`, or any other Rails file before they are applied, providing complete oversight and preventing unintended modifications.

## Steps

1. Identify independent slices for your Ruby on Rails audit, such as `app/models`, `app/controllers`, or `spec/` directories, to prevent subagent overlap.
2. Launch multiple `task` calls concurrently, specifying `subagent_type explore` for read-only sweeps of your Rails codebase. For example, `atlas task 'audit app/models for N+1 queries' subagent_type explore` and `atlas task 'audit app/controllers for security issues' subagent_type explore`.
3. If a subagent needs to run commands like `bundle exec rubocop` or `bundle exec rspec` for its audit, use `subagent_type general` and ensure appropriate permission rules are set.
4. Monitor the main Atlas session as subagents complete their tasks, collecting their final messages and any reported errors or cancellations.
5. Use the `todowrite` tool to consolidate all findings from the parallel subagents into a single, actionable list of issues for your Ruby on Rails project.
6. Address the identified issues in the main Atlas session using the `edit` tool, reviewing the unified diff for each proposed change to your Rails files before approval.
7. Utilize Atlas's `grep` and `glob` tools within the main session to further investigate specific patterns or file sets identified by the subagents, such as all files matching `app/models/**/*.rb`.
8. Once fixes are applied, use Atlas to stage and create commits, leveraging its ability to read git branches, status, and diffs on your behalf.

## FAQ

### How does Atlas handle large Ruby on Rails codebases during an audit?

Atlas handles large Ruby on Rails codebases by fanning out audit tasks to parallel subagents. Each subagent works on a specific slice of the repository, such as `app/models` or `spec/`, ensuring that the main session's context window remains clear and efficient.

### Can Atlas run `RSpec` tests or `RuboCop` checks within a subagent?

Yes, Atlas can run `RSpec` tests or `RuboCop` checks within a subagent. For tasks requiring command execution, you would use `subagent_type general`. Atlas ensures all tool calls, including `bundle exec rspec` or `bundle exec rubocop`, are permission-gated for safety.

### What kind of files can Atlas audit in a Ruby on Rails project?

Atlas can audit any files in a Ruby on Rails project, including `app/models/**/*.rb`, `app/controllers/**/*.rb`, `db/migrate/**/*.rb`, `Gemfile`, `config/application.rb`, and `spec/**/*.rb`. It indexes code by AST declarations using tree-sitter for precise understanding.

### How does Atlas prevent accidental changes during a Ruby on Rails audit?

Atlas prevents accidental changes during a Ruby on Rails audit through several safety features. The `explore` subagent type is deny-by-default and read-only. Additionally, all tool calls are permission-gated, and any proposed file edits are presented as a unified diff for your explicit approval before being written.

### Can I use local Ollama embeddings for my Ruby on Rails code with Atlas?

Yes, Atlas can build its code index with local Ollama embeddings. This feature allows you to keep your Ruby on Rails codebase off third-party servers, enhancing privacy and security during your audit process.

### How do I consolidate findings from multiple subagents in a Rails audit?

After multiple subagents complete their audit tasks on your Rails project, Atlas automatically collects their final messages. You then use the `todowrite` tool in the main Atlas session to merge these individual findings into a single, actionable list for review and remediation.

### What is the benefit of parallel subagents for Ruby on Rails audits?

The primary benefit of parallel subagents for Ruby on Rails audits is efficiency. They allow you to sweep an entire repository for a class of problem much faster by processing different parts of the codebase concurrently, without overwhelming the main session's context window.

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