Rules¶

A rule is stable, preview (it runs only with preview = true), deprecated (it will be removed) or removed (documented for history).

architecture¶

How modules depend on each other: the layers and the direction of the imports.

Code	Rule	Standard	Status	Added in	Default
`BTARCH001`	`import-layers` A layer imports nothing of a layer above it imports	CES-5	stable	0.12.0	on
`BTARCH002`	`separate-orchestration` A function either orders the steps or does one of them design	CES-8	preview	0.13.0	off
`BTARCH003`	`architecture-vocabulary` Units are named with the architectural vocabulary of the house naming	CES-16	preview	0.13.0	off

What a run reports about itself: unreadable paths and suppression comments.

Code	Rule	Status	Added in	Default
`BT001`	`io-error` A path given on the command line cannot be read	stable	0.7.0	on
`BT002`	`unused-suppression` A suppression comment that silences nothing	stable	0.7.0	on
`BT003`	`invalid-suppression` A suppression comment that names an unknown rule or is malformed	stable	0.7.0	on
`BT004`	`external-config` The file that an active external rule names holds the configuration of its tool	stable	0.10.0	on

How command-line programs are written: the parser of the arguments.

Code	Rule	Standard	Status	Added in	Default
`BTCLI001`	`cli-typed-framework` Command-line interfaces use a typed, declarative framework cli	CES-67	stable	0.8.0	on

How a program reads its configuration: the settings module, its class and the schema of the environment.

Code	Rule	Standard	Status	Added in	Default
`BTCONF001`	`settings-module` Environment is read only in the settings module config	CES-76	stable	0.8.0	on
`BTCONF002`	`settings-base-class` A settings class extends BaseSettings, not BaseModel config	CES-76	preview	0.10.0	off
`BTCONF003`	`settings-direct-instantiation` Settings are read through get_settings(), never built where they are used config	CES-76	preview	0.10.0	off
`BTCONF004`	`settings-env-schema` The variables of .env.schema and the fields of the settings classes match config	CES-76	stable	0.12.0	on

Typed data at the boundaries: schemas, models, no raw dicts.

Code	Rule	Standard	Status	Added in	Default
`BTDM001`	`no-dict-alias` No type alias that hides a raw dict typing	CES-79	stable	0.8.0	on
`BTDM002`	`no-dict-call-return` No function returning dict(...) typing	CES-79	stable	0.8.0	on
`BTDM003`	`no-dict-literal-return` No function returning a dict literal typing	CES-79	stable	0.8.0	on
`BTDM004`	`no-dict-return-annotation` No function annotated to return a raw dict typing	CES-79	stable	0.8.0	on

How code reaches a relational database: where the tables live and how the schema changes.

Code	Rule	Standard	Status	Added in	Default
`BTDB001`	`database-package` Relational persistence lives in a database package layout	CES-18	stable	0.8.0	on
`BTDB002`	`db-no-create-all` The schema changes through migrations, not metadata.create_all() layout	CES-18	preview	0.10.0	off

Rules for FastAPI services.

Code	Rule	Standard	Status	Added in	Default
`BTFAST001`	`api-schemas-extra-forbid` Request and response schemas reject unknown fields typing	CES-4	stable	0.8.0	on
`BTFAST002`	`api-schema-in-route-module` Pydantic schemas are not defined in route modules typing	CES-17	preview	0.10.0	off
`BTFAST003`	`api-request-schema-name` Request schemas are named {Name}Request typing	CES-17	preview	0.10.0	off
`BTFAST004`	`api-response-schema-name` Response schemas are named {Name}Response typing	CES-17	preview	0.10.0	off

How code logs and what it must not print.

Code	Rule	Standard	Status	Added in	Default
`BTLOG001`	`log-get-logger` Loggers come from the house get_logger logging	CES-45	stable	0.8.0	on
`BTLOG002`	`log-no-print` Libraries log, they don't print logging	CES-46	stable	0.8.0	on

How changes are made: the scope of a pull request and its commits.

Code	Rule	Standard	Status	Added in	Default
`BTPROC001`	`pr-small-by-intent` A pull request carries one intent review	CES-122	preview	0.13.0	off
`BTPROC002`	`respect-local-repo` A change keeps the deliberate choices of the repository review	CES-30	preview	0.13.0	off
`BTPROC003`	`conventional-commits` Every commit subject follows Conventional Commits commits	CES-75	preview	0.14.0	off
`BTPROC004`	`no-ai-coauthorship` A commit message names no AI tool as a co-author or as the author of the change commits	CES-91	preview	0.14.0	off

How code handles credentials: who checks them, how a token is decoded and where the browser keeps it.

Code	Rule	Standard	Status	Added in	Default
`BTSEC001`	`route-auth` Each route gets its caller from a dependency that verifies a credential auth, fastapi	CES-121	preview	0.13.0	off
`BTSEC002`	`jwt-verified` A decoded token has its signature and its expiry checked auth, jwt	CES-121	preview	0.13.0	off
`BTSEC003`	`no-token-in-web-storage` The browser keeps no credential in web storage auth, browser	CES-121	preview	0.13.0	off

Where code lives and how big it gets: file size, module naming, repository layout.

Code	Rule	Standard	Status	Added in	Default
`BTSTRUC001`	`file-size-guard` Keep source files small size	CES-71	stable	0.7.0	on
`BTSTRUC002`	`no-utils` No catch-all modules naming	CES-63	stable	0.7.0	on
`BTSTRUC003`	`no-artifacts-in-package` Keep data, models and reports outside the code layout	CES-32	stable	0.7.0	on
`BTSTRUC004`	`no-notebooks` Keep Jupyter notebooks outside the code layout	CES-32	stable	0.7.0	on
`BTSTRUC005`	`no-tests-in-package` Keep tests beside the package, not in it layout	CES-32	stable	0.7.0	on
`BTSTRUC006`	`cognitive-complexity` A function has a cognitive complexity of at most 15 complexity	CES-110	preview	0.10.0	off
`BTSTRUC007`	`lockfile-committed` Each manifest has the lockfile of one package manager, committed dependencies	CES-109	preview	0.13.0	off

How tests are written and run.

Code	Rule	Standard	Status	Added in	Default
`BTTEST001`	`test-in-memory-adapters` Tests drive the logic through in-memory adapters, not mocks tests	CES-64	preview	0.13.0	off
`BTTEST002`	`test-through-interface` Tests assert on behaviour through the public interface tests	CES-65	preview	0.13.0	off
`BTTEST003`	`test-coverage-gap` A coverage gap is closed with a test that asserts a behaviour tests, coverage	CES-66	preview	0.13.0	off
`BTTEST004`	`no-coverage-pragma` No `# pragma: no cover` hides code from the coverage report tests, coverage	CES-66	preview	0.14.0	off
`BTTEST005`	`no-coverage-exclusion` The configuration of coverage leaves no code out of the report and keeps its threshold tests, coverage	CES-66	preview	0.14.0	off
`BTTEST006`	`coverage-exclusion-reachable` Coverage leaves out only code that no test can reach tests, coverage	CES-66	preview	0.14.0	off

How the tools that check the code are configured: what keeps them on.

Code	Rule	Standard	Status	Added in	Default
`BTTOOL001`	`no-disabled-typecheck` The type checker stays on for the whole build and every file types	CES-58	preview	0.13.0	off

How text is written: documentation, commit messages, comments and the terms of the domain.

Code	Rule	Standard	Status	Added in	Default
`BTWRIT001`	`plain-writing` Text has none of the signs of model writing writing	CES-120	preview	0.13.0	off
`BTWRIT002`	`minimal-comments` A comment says only what the code cannot writing	CES-120	preview	0.13.0	off
`BTWRIT003`	`ubiquitous-language` One term per concept of the domain, the one of the glossary writing	CES-120	preview	0.13.0	off