architecture-fit-check

Architecture Fit Check

This skill provides the framework for evaluating whether proposed change-set specs (especially kind: delta) can be implemented within the existing codebase architecture.

Primary Question

Can an implementer translate these change-set specs into the repo's current architecture with routine changes + small refactors?

The answer is not about whether change-set specs align with canonical capability specs — canonical specs describe what the system does, not how it's built. Evaluate fit against the actual codebase architecture.

Process

1. Research the Repo Architecture

Use the research skill to understand the codebase:

• "What are the main architectural layers and module boundaries?"
• "Where are the entry points and how do they call into core logic?"
• "What patterns exist for dependency injection, interfaces, or adapters?"
• "Is there any existing eventing, pubsub, job queue, or workflow pattern?"
• "Find precedent implementations similar to these delta requirements."

Do not skip this step. You cannot evaluate fit without understanding how the repo is actually built.

2. Identify Constraints

Based on research, identify constraints that matter:

• Structural: Module boundaries, dependency directions, layering rules
• Behavioral: Error handling, state management, concurrency model
• Interface: API contracts, extension points, data formats
• Operational: Testing approach, build/CI, runtime model

3. Evaluate Each Delta Against Constraints

For each capability being added/modified:

• Can it be implemented using existing patterns?
• Does it require crossing boundaries in new ways?
• Does it introduce new primitives the repo doesn't have?

4. Check for Workaround Smell

Before finalizing, ask yourself:

• Am I proposing adjustments that are really just glue/hacks?
• Would these adjustments create inconsistent patterns?
• Is the "fit" path creating tech debt just to avoid a paradigm discussion?

If yes to any, the verdict should recommend paradigm work.

Verdicts

FITS

Choose when:

• All constraints satisfied
• Changes follow existing patterns
• Implementation stays inside 1-2 domains/modules
• No new "system primitive" required

FITS_WITH_ADJUSTMENTS

Choose when:

• Minor constraint violations fixable with targeted work
• Adjustments are truly minimal and localized
• Examples: new module boundary, new interface + adapter, extract small utility

NO_FIT

Choose when:

• Clean solution requires a new paradigm many modules must participate in
• Would require reorganizing layering/dependency direction repo-wide
• Changes runtime/operational assumptions

Output Format

Document your findings:

## Architecture Fit Evaluation

### Verdict: FITS | FITS_WITH_ADJUSTMENTS | NO_FIT

### Constraints Evaluated
- <List of architecture constraints checked>

### Satisfied
- <Constraints that pass>

### Violated
- <Constraints that fail, or "None">

### Minimal Adjustments (if FITS_WITH_ADJUSTMENTS)
- <Specific changes needed>

### Paradigm Work Needed (if NO_FIT)
- <What kind of new mechanism is required>
- Load the `paradigm-design` skill to explore options