Detection

af init reads what is already in the repository and writes a manifest from it. Every value it writes came from a file: a package manifest, a Dockerfile, a compose file, a dependency list.

af init

It does not ask you to describe your application. Your application already describes itself, in the files you use to run it.

What it reads

Source	What it yields
`package.json`, `go.mod`, `requirements.txt`, `Gemfile`	Language, version, start command, scripts
`Dockerfile`, `docker-compose.yml`, `Procfile`	Services, ports, commands, dependencies
Dependency lists	Third party APIs, which become egress rules
Migration directories	The migrate command
Cron and schedule files	Scheduled services
`*.tf` files	The Terraform root modules, which become `infrastructure.stacks`

The dependency list is the one that surprises people. A stripe dependency produces an egress rule for api.stripe.com in sandbox mode, a resend dependency produces one for api.resend.com in capture mode, and a sentry dependency produces a block with a sentence saying why.

Terraform is the one source where finding the files is not the whole job. Every directory holding a .tf file is a module and most of them are not root modules, so detection reads the module blocks, takes out the directories something calls with a local source, and drafts what is left: the units that are planned and applied on their own. A repository that only publishes modules gets no section and a sentence saying why, because “we found no infrastructure” and “we found only building blocks” are different facts.

It never drafts a stack’s workspace or var_files, and it says so under its own heading. Which workspace holds production, and which of production.tfvars, staging.tfvars and dev.tfvars describes it, is not stated anywhere in a repository. A file name is not a fact, and this is the one section of the manifest that describes production rather than the copy, so nothing downstream could catch a wrong answer.

What it says it is unsure about

Assumed
  database.present                         yes
  service.web.port                         3000

  These were not detected with confidence. Check them before you commit.

A guess presented as a fact is worse than a question. Anything inferred rather than read is listed under Assumed, so the things worth a second look are the short list rather than the whole file.

Every question has a default, so a run with nobody at the terminal still finishes. A port with no evidence defaults per language: 3000 for node and ruby, 8000 for python, 8080 for go. A start command with no evidence defaults to the conventional one where the language has one, such as npm start or go run ., and a service where nothing can be guessed is dropped from the draft with a note rather than failing the command. When standard input is not a terminal, af init behaves as --non-interactive does: it takes every default and lists each one under Assumed, which is also what af ci does when it drafts a manifest for a repository that has none.

When it cannot decide

AF-DET-001 More than one service could be the web service: web, api, frontend.

Rather than picking one, it says which candidates it found. Editing the manifest once is faster than discovering next week that previews have been building the wrong thing.

Re-running it

af init writes the manifest once and does not regenerate it. Nothing rewrites it behind your back, so an edit you make survives, and a later af init on a repository that already has one tells you it is there rather than replacing it.

If the repository has changed enough to want a fresh look, delete the manifest and run it again, or read the new one against the old with git diff.