DevTools import boundaries

Every @devtools/* package is self-contained. The only permitted cross-package imports within the devtools scope are listed in the table below; all others are forbidden.

Rules

| Package | May import from @devtools/* | |---|---| | @devtools/registry | any @devtools/<tool> | | @devtools/shell | @devtools/transport, @devtools/registry | | @devtools/bindings | @devtools/registry only | | @devtools/wire | @devtools/transport, @devtools/protocols | | @devtools/protocols | @devtools/transport only | | @devtools/relay | @devtools/transport only | | @devtools/transport-panel | @devtools/transport only | | @devtools/<tool> | none |

All other @devtools/* → @devtools/* imports are forbidden.

Why

The devtools architecture decouples tools from the shell through the registry. The shell lazy-loads tools via metadata.loader; tools never know the shell exists. If a tool imports the shell or another tool directly:

• The lazy-load boundary collapses — the tool is bundled eagerly.
• A circular dependency becomes likely (tool → shell → registry → tool).
• The tool can no longer be rendered standalone, outside the shell.

If bindings or shell import a tool package directly (instead of through the registry):

• The registry's discriminated union is bypassed and TypeScript loses the narrowing guarantee on DevToolsConfig.
• The import() split point disappears, defeating code-splitting.

Consequences of a violation

• Tool imports shell or registry: The tool becomes coupled to shell internals; standalone rendering and unit-testing break.
• Tool imports another tool: Cross-tool coupling; removing or renaming one tool requires editing the other.
• Shell or bindings import a tool directly: Eager bundle; code-split lost; registry union integrity broken.

Correct pattern

Cross-cutting concerns (shared types, utilities) must not live in a tool package. Extract them to a standalone library with no @devtools/* scope, then import that from whichever packages need it.

App state and wiring for a tool arrive as props, built in @devtools/bindings — the single sanctioned bridge to Ledger Live internals. A tool that needs more data from the app gets new props, not a new import.

Documentation

When adding a new package under devtools/, its README.md must state:

• Which @devtools/* packages it may import, per the table above.
• That all other @devtools/* imports are forbidden, with a pointer to this rule.