How does Atlas understand Symfony's service container and autowiring?

Atlas indexes code by AST declarations using tree-sitter, allowing it to understand the structure of your Symfony services, including those defined in `config/services.yaml` and autowired dependencies. It can follow `lsp goToDefinition` calls to trace service injections.

Can Atlas help me understand Doctrine entities and migrations in a new Symfony project?

Yes, Atlas can read your Doctrine entity mappings in `src/Entity/` and understand their relationships. It can also run `bin/console doctrine:migrations:diff` and show you the generated SQL for review before any changes are applied to a database.

How does Atlas ensure I don't accidentally change code while exploring a Symfony codebase?

Atlas employs a read-only plan agent and a permission-gated `explore` subagent with a deny-by-default rule set. This ensures that while you are exploring, no modifications can be made to your Symfony files, such as `config/routes.yaml` or `composer.json`.

What Symfony-specific files does Atlas prioritize for indexing and understanding?

Atlas is configured to read and index critical Symfony files like `composer.json`, `config/services.yaml`, `config/routes.yaml`, and your controllers and Doctrine entity mappings. This allows it to build a comprehensive understanding of your application's structure.

Can Atlas help me find where a specific Symfony route is defined or used?

Absolutely. You can use `codebase_search` to ask 'where is the `/admin/dashboard` route defined?' or 'show me usages of the `app_homepage` route'. Atlas will return relevant snippets from `config/routes.yaml` or controller annotations.

How does Atlas integrate with Symfony's testing framework, `PHPUnit (WebTestCase)`?

Atlas can add `PHPUnit WebTestCase` coverage to your Symfony application. After making changes, it can also run `PHP-CS-Fixer` over the diff to ensure code style consistency, and then present the test results for your review.

Does Atlas support Symfony's `bin/console` commands for development tasks?

Yes, Atlas can expose tools from Model Context Protocol servers, allowing it to interact with and leverage Symfony's `bin/console` commands. For example, it can run `bin/console cache:clear` or `bin/console debug:autowiring` on your behalf, with your explicit permission.

Onboard to an Unfamiliar Symfony Codebase with Atlas in 2026

Atlas helps Symfony developers in 2026 build a working mental model of an unfamiliar repository without reading every file by combining semantic code search, intelligent file exploration, and deep integration with the Symfony toolchain, including `Composer` and `PHPUnit (WebTestCase)`.

How does Atlas help explore an unfamiliar Symfony codebase?

Atlas streamlines initial exploration of an unfamiliar Symfony codebase in 2026 by starting from meaning, not filenames. It uses `codebase_search` to query a semantic index, `glob` to map directory structures like `src/Controller`, and `read` to pull only the 2-3 most relevant files.

When you encounter a new Symfony project, Atlas begins by understanding the code's intent. Ask `codebase_search` 'how requests are authenticated' to find relevant snippets in `src/Security` or `src/Controller`. Atlas queries its semantic index, built by AST declarations, returning ranked file paths. The `glob` tool then provides a high-level overview of the project's layout, revealing Symfony conventions like `src/Controller`, `config/`, and `templates/` directories. Finally, `read` allows you to pull the top two or three files identified, giving you a focused starting point within the Symfony application.

How does Atlas build a mental model of Symfony services and entities?

Atlas builds a working mental model of Symfony's intricate components by leveraging the `lsp` tool's `goToDefinition` operation. After reading initial files, you can follow imports to understand autowired services defined in `config/services.yaml` or trace Doctrine entity mappings, significantly reducing the time spent on manual navigation in 2026.

After identifying initial files, Atlas deepens your understanding of Symfony's architecture. The `lsp` tool's `goToDefinition` operation is crucial for tracing dependencies. For instance, from a controller in `src/Controller/`, use `lsp goToDefinition` on an injected service to jump directly to its definition, often configured in `config/services.yaml`. Similarly, navigate from a repository method to its Doctrine entity definition in `src/Entity/`, or explore routes in `config/routes.yaml`. This capability allows you to quickly map out the service container, understand entity relationships, and grasp control flow without exhaustive manual file searching.

How does Atlas safely explore a large Symfony repository?

For wide-ranging exploration in a large Symfony repository, Atlas delegates work to the `explore` subagent through the `task` tool. This subagent operates with a deny-by-default permission set, allowing only read-only operations like `grep`, `glob`, `read`, `bash`, `webfetch`, and `websearch`, ensuring no accidental changes occur while you investigate in 2026.

For wide-ranging exploration in a large Symfony codebase, Atlas delegates tasks to the `explore` subagent via the `task` tool. This subagent operates with a deny-by-default permission set, allowing only read-only operations. It can `grep` for patterns (e.g., finding all usages of a Symfony event listener), `glob` directory structures, `read` file contents, `bash` for safe shell commands, `webfetch` for external documentation, and `websearch`. This robust permission model ensures that the subagent cannot inadvertently modify any Symfony configuration files, service definitions, or entity mappings, providing a secure environment for deep investigation.

How does Atlas ensure safety and review for Symfony code changes?

Atlas incorporates multiple safety and review mechanisms to protect your Symfony codebase. Every Atlas tool call is permission-gated against `allow`, `ask`, and `deny` rules. Before any changes are written, Atlas drafts a plan in a read-only agent, computes a unified diff for every file edit, and surfaces it for your approval, ensuring full control over your Symfony project in 2026.

Atlas prioritizes the integrity of your Symfony codebase through multi-layered safety. Every tool call is permission-gated, allowing `allow`, `ask`, or `deny` rules for operations like modifying `config/services.yaml`. When Atlas proposes a change, it first drafts a plan in a read-only agent for your review. For every file edit, Atlas computes a unified diff, presenting it for approval. This allows meticulous review of proposed changes to Symfony controllers, services, or Doctrine entities before writing. Atlas also integrates with `git`, reading branches and diffs, and can stage and create commits on your behalf, ensuring changes are tracked and reversible.

How does Atlas help record and track onboarding progress in Symfony?

To ensure continuity and prevent loss of insights during Symfony onboarding, Atlas provides the `todowrite` tool. This allows you to record what you learned, capture open questions about specific bundles or services, and create actionable to-do lists that persist across your Atlas sessions in 2026, making your progress tangible.

Building a mental model of a new Symfony codebase involves accumulating many insights and questions. Atlas supports this with the `todowrite` tool. As you explore, use `todowrite` to jot down key findings, such as a service's purpose, a Doctrine entity's structure, or a request's flow through a controller. Crucially, `todowrite` captures open questions or areas needing further investigation, ensuring these insights persist across sessions. This prevents re-discovering information and maintains a clear, actionable list of remaining tasks, whether understanding a custom `Composer` script or debugging a `PHPUnit (WebTestCase)` failure.

Step by step

01Start Atlas in your Symfony application's root directory, ensuring `composer.json` and `config/services.yaml` are present for indexing.
02Ask `codebase_search` a plain-language question, like 'how are requests authenticated in Symfony?' to find relevant snippets in `src/Security` or `src/Controller`.
03Run `glob` on the top-level directories (e.g., `src/`, `config/`, `templates/`) to understand the Symfony bundle and package layout.
04Use `read` on the two or three highest-ranked files from `codebase_search`, then follow Symfony service injections or Doctrine entity relationships with `lsp goToDefinition`.
05Delegate wide sweeps to the `explore` subagent via the `task` tool, for example, 'task explore: find all usages of the `LoggerInterface` service across the codebase' to understand logging patterns.
06Record what you learned about Symfony services, controllers, or entities as a `todowrite` list, ensuring open questions about `config/routes.yaml` or custom bundles persist.

Frequently asked questions

How does Atlas understand Symfony's service container and autowiring?: Atlas indexes code by AST declarations using tree-sitter, allowing it to understand the structure of your Symfony services, including those defined in `config/services.yaml` and autowired dependencies. It can follow `lsp goToDefinition` calls to trace service injections.
Can Atlas help me understand Doctrine entities and migrations in a new Symfony project?: Yes, Atlas can read your Doctrine entity mappings in `src/Entity/` and understand their relationships. It can also run `bin/console doctrine:migrations:diff` and show you the generated SQL for review before any changes are applied to a database.
How does Atlas ensure I don't accidentally change code while exploring a Symfony codebase?: Atlas employs a read-only plan agent and a permission-gated `explore` subagent with a deny-by-default rule set. This ensures that while you are exploring, no modifications can be made to your Symfony files, such as `config/routes.yaml` or `composer.json`.
What Symfony-specific files does Atlas prioritize for indexing and understanding?: Atlas is configured to read and index critical Symfony files like `composer.json`, `config/services.yaml`, `config/routes.yaml`, and your controllers and Doctrine entity mappings. This allows it to build a comprehensive understanding of your application's structure.
Can Atlas help me find where a specific Symfony route is defined or used?: Absolutely. You can use `codebase_search` to ask 'where is the `/admin/dashboard` route defined?' or 'show me usages of the `app_homepage` route'. Atlas will return relevant snippets from `config/routes.yaml` or controller annotations.
How does Atlas integrate with Symfony's testing framework, `PHPUnit (WebTestCase)`?: Atlas can add `PHPUnit WebTestCase` coverage to your Symfony application. After making changes, it can also run `PHP-CS-Fixer` over the diff to ensure code style consistency, and then present the test results for your review.
Does Atlas support Symfony's `bin/console` commands for development tasks?: Yes, Atlas can expose tools from Model Context Protocol servers, allowing it to interact with and leverage Symfony's `bin/console` commands. For example, it can run `bin/console cache:clear` or `bin/console debug:autowiring` on your behalf, with your explicit permission.

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