Atlas is a terminal-native AI coding agent you run inside a Symfony app. In 2026 you start atlas in an app with a composer.json and a config/services.yaml, and Atlas reads your controllers, autowired services, Doctrine entity mappings, and the routes in config/routes. Every file edit arrives as a unified diff, and every generated migration shows you its SQL before it goes near a database.
Why Symfony developers use Atlas
Symfony developers use Atlas in 2026 because bundles, the service container, and Doctrine entities form a graph that no single file explains. Atlas indexes code by AST declarations using tree-sitter, not blind line windows, so an autowired service and the controller that consumes it resolve to real class declarations.
Symfony's power is indirection. A controller receives a service it never constructs, the container resolves it from config/services.yaml plus autowiring rules, and Doctrine maps an entity to a table through attributes that live somewhere else again. Atlas searches code with hybrid semantic and keyword retrieval fused by reciprocal rank fusion, so a question about where a service is configured returns the services.yaml entry and the class, not one or the other. The AST index keeps attributes attached to the classes and methods they decorate, which is what a container or Doctrine answer requires.
How Atlas reads the Symfony service container and Doctrine mappings
Start Atlas in an app with a composer.json and a config/services.yaml, and Atlas reads your controllers, autowired services, Doctrine entity mappings, and the routes in config/routes. Symfony spreads one behavior across 3 places, and Atlas holds all of them at once.
Atlas walks config/services.yaml for explicit definitions and argument bindings, then reads the constructor signatures that autowiring depends on. It maps Doctrine entities to their table mappings and relations, and it reads the routes in config/routes so an endpoint can be traced from URL to controller action to injected service. When a Symfony app is large enough that this survey takes a while, Atlas fans out work to subagents that can run in the foreground or in parallel background sessions, so the mapping does not block the change you asked for.
Moving fat controllers into services and Messenger handlers
Ask Atlas to move a fat controller into an injected service, or add a Symfony Messenger handler. A Symfony controller that has grown past 200 lines is usually carrying business logic that belongs behind the service container or on the message bus.
Atlas reads the controller action, identifies the logic that does not belong to HTTP, and proposes an injected service with the same behavior, wiring the constructor argument so autowiring resolves it. When the work should be asynchronous, Atlas proposes a Symfony Messenger message and handler instead, and registers the handler where the container expects it. Atlas computes a unified diff for every file edit and surfaces it for approval before writing, so the thinned controller, the new service, and the config change land as one reviewable set of hunks.
Doctrine migrations: see the SQL before it runs
Atlas runs bin/console doctrine:migrations:diff and shows you the generated SQL before anything runs against a database. In 2026 a Doctrine migration is still the one Symfony change that cannot be reverted by editing a file, so Atlas puts the SQL in front of you first.
Atlas treats the database as the highest-risk surface in a Symfony app. It runs bin/console doctrine:migrations:diff, reads the generated migration class, and shows you the up SQL it would execute. Every Atlas tool call is permission-gated against allow, ask, and deny rules before it runs, so you can allow the diff command while leaving anything that applies a migration on ask, or deny it outright in a production checkout. Nothing touches the database until you say so, and the migration class itself is a reviewable diff like any other file.
Testing with PHPUnit WebTestCase and formatting with PHP-CS-Fixer
Atlas adds PHPUnit WebTestCase coverage, then runs PHP-CS-Fixer over the diff. A Symfony WebTestCase boots the real kernel, so 1 test exercises the routes in config/routes, the service container, and the Doctrine layer together rather than a mocked approximation of any of them.
Atlas writes WebTestCase cases against the routes it just changed, using the real client to hit the endpoint and assert on the response, which proves that the extracted service is actually wired into the container. Then it runs PHP-CS-Fixer over the diff so the change matches your existing style. Atlas snapshots file changes as git patches, so a controller extraction that turns out wrong is a rollback rather than a manual undo, and Atlas reads git branches, status, and diffs and can stage and create commits on your behalf.
Getting started
- 01Run atlas in an app with a composer.json and a config/services.yaml
- 02Let Atlas read your controllers, autowired services, Doctrine entity mappings, and the routes in config/routes
- 03Ask Atlas to move a fat controller into an injected service, or add a Symfony Messenger handler
- 04Let Atlas run bin/console doctrine:migrations:diff and show you the generated SQL before anything runs against a database
- 05Have Atlas add PHPUnit WebTestCase coverage, then run PHP-CS-Fixer over the diff
Frequently asked questions
- how to use an AI coding agent with symfony
- Run atlas in an app with a composer.json and a config/services.yaml. Atlas reads your controllers, autowired services, Doctrine entity mappings, and the routes in config/routes, then proposes edits as unified diffs you approve.
- can an AI agent generate doctrine migrations safely
- Atlas runs bin/console doctrine:migrations:diff and shows you the generated SQL before anything runs against a database. Every tool call is permission-gated against allow, ask, and deny rules first.
- how do i refactor a fat symfony controller
- Ask Atlas to move a fat controller into an injected service, or add a Symfony Messenger handler. Atlas wires the constructor argument so autowiring resolves it and shows the whole change as a diff.
- can atlas write phpunit tests for symfony
- Yes. Atlas adds PHPUnit WebTestCase coverage against the routes it changed, which boots the real kernel and exercises the container and Doctrine layer, then runs PHP-CS-Fixer over the diff.
- does atlas understand symfony autowiring
- Yes. Atlas indexes code by AST declarations using tree-sitter, not blind line windows, and reads config/services.yaml alongside constructor signatures, so it resolves how a service is actually injected.
- does atlas upload my symfony code to a third party
- Not necessarily. Atlas can build its code index with local Ollama embeddings, keeping code off third-party servers, which suits agency and enterprise Symfony work.
- can i roll back an atlas change to a symfony service
- Yes. Atlas snapshots file changes as git patches so edits can be diffed and rolled back, and it can stage and create commits on your behalf once the change is reviewed.
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