Architecture Policy

Purpose

This document defines Promptkit's current high-level architecture and the durable boundaries that implementation changes must preserve. The internal component overview inventories concrete implemented packages without redefining these rules.

System Shape

Promptkit is an importable Go library. It does not provide a runnable command, an HTTP service, or another application process.

The module root contains package promptkit, which is the public facade and the only implemented Go package in the current repository foundation. It declares the module's public package boundary but does not yet provide migrated framework behavior or exported APIs. No internal framework packages currently exist.

Future framework extraction must follow this dependency direction:

downstream consumers, including Scriptorium
                    |
                    v
       root promptkit public facade
                    |
                    v
       internal framework components
                    |
                    v
        narrow injected abstractions

The facade may coordinate internal components. Internal components must depend on narrow abstractions for behavior supplied from outside the library; they must not depend on consumers or on Scriptorium. This diagram constrains future work and does not assert that the internal components already exist.

Repository And Consumer Boundary

Scriptorium is a downstream application that will consume Promptkit through the supported public facade. It is not a Promptkit package and must not become an internal dependency.

Promptkit owns reusable, application-neutral library behavior. It does not own:

binaries or executable packaging;
CLI commands, parsing, streams, or exit codes;
HTTP routes, servers, request DTOs, status mapping, or deployment policy;
application configuration discovery or precedence;
process lifecycle, operational state, or application logging; or
consumer-specific filesystem or security policy.

Those concerns remain with Scriptorium or another consuming application.

Package Ownership

The module root is the supported public facade. Framework implementation packages belong under Go's internal/ boundary unless a demonstrated, stable consumer contract requires a public package.

Each package must have one cohesive responsibility and a clear dependency direction. Internal packages must not expose their types merely to simplify wiring, and the public facade must not leak internal representations through exported signatures. New public packages require a durable consumer need that cannot be served cleanly by the root facade.

The internal component overview must be updated as packages are implemented or their responsibilities change.

Exported API Discipline

Export the smallest contract required by real consumers. Exported declarations must have accurate GoDoc, stable semantics, and tests proportionate to their compatibility risk. Avoid speculative extension points, aliases for internal types, and public constructors that expose assembly details.

Once an exported API exists, its Go declaration and GoDoc own its exact public contract. Architecture documentation owns boundary rules, not a duplicate API reference.

Error Boundaries

Internal failures must cross the public facade as errors meaningful to a Go consumer without exposing private package types or transport-specific policy. Wrapping should add useful context while preserving any public error identity needed with errors.Is or errors.As.

Promptkit must not assign CLI exit codes or HTTP status codes. Consumers map public library outcomes into their own transport behavior.

Dependency Injection

External effects and consumer-selected policy must enter through narrow interfaces or functions at the boundary that uses them. Dependencies should be explicitly supplied during construction or invocation rather than read from consumer configuration or hidden process-global state.

Interfaces should be owned by the code that consumes the behavior and should contain only the operations that code requires. Provide defaults only for application-neutral behavior; consumer-specific restrictions and adapters remain injected from the consuming project.

Repository Independence

Promptkit must build, test, and validate independently of Scriptorium. Do not commit go.work, go.work.sum, or a local filesystem replace directive. Temporary workspace or replacement configuration may support coordinated local development, but it is not part of either repository's architecture or release state.

Current-State Maintenance

This policy distinguishes present implementation from constraints on future framework extraction. Do not list planned packages as implemented components. When extraction introduces a package, update the internal inventory and the owning contract or subsystem document in the same change.

4.9 KiB Raw Blame History