Companion Plugins

Companion plugins are standalone Claude Code plugins that add quality dimensions to Exarchos reviews. They install separately and integrate automatically -- no configuration required.

Available plugins

axiom (backend quality)

Seven dimensions covering general backend code quality:

Dimension	Scope
DIM-1 Topology	Module boundaries, dependency direction, coupling
DIM-2 Observability	Logging, metrics, tracing coverage
DIM-3 Contracts	API schemas, type safety at boundaries
DIM-4 Test Fidelity	Test isolation, assertion quality, coverage gaps
DIM-5 Hygiene	Dead code, TODOs, lint suppressions, formatting
DIM-6 Architecture	Pattern consistency, layer violations
DIM-7 Resilience	Error handling, retry logic, timeout coverage

Install (axiom is on the lvlup-sw marketplace, which ships with Exarchos):

claude plugin install axiom@lvlup-sw

impeccable (frontend design quality)

Covers design and UI concerns:

• UI consistency -- component reuse, spacing systems, visual rhythm
• Accessibility -- ARIA, keyboard navigation, color contrast
• Design system compliance -- token usage, component variants
• Responsive design -- breakpoints, layout shifts, touch targets

Install (impeccable has its own marketplace):

claude plugin marketplace add pbakaus/impeccable
claude plugin install impeccable@impeccable

How detection works

Zero-config. During review, Exarchos checks whether the axiom:audit and impeccable:critique skills are available. If a skill is present (meaning the plugin is installed), Exarchos invokes it and merges the findings into the review.

No skill detected? Exarchos skips it silently. No errors, no warnings. The review runs with its native dimensions only.

Configuration override

Both plugins are enabled by default when installed. To disable one, add a plugins section to .exarchos.yml:

plugins:
  axiom:
    enabled: true
  impeccable:
    enabled: false

This is per-project. A backend-only repo might disable impeccable. A project happy with native dimensions can disable both.

Dimension ownership

Each quality dimension belongs to exactly one owner:

Owner	Dimensions
axiom (optional)	DIM-1 Topology, DIM-2 Observability, DIM-3 Contracts, DIM-4 Test Fidelity, DIM-5 Hygiene, DIM-6 Architecture, DIM-7 Resilience
impeccable (optional)	UI consistency, accessibility, design system compliance, responsive design
exarchos (always)	D1 Spec Fidelity & TDD, D2 Static Analysis, D3 Context Economy, D5 Workflow Determinism

Exarchos native dimensions (D1-D5) always run. Plugin dimensions only run when the plugin is installed and enabled.

Three-tiered review model

What you get depends on what's installed:

MCP-only (any client, no Claude Code): Exarchos native dimensions D1-D5. Convergence gates, verdicts, fix cycles. The full workflow engine minus the content layer.

Claude Code (Exarchos plugin only): Everything above, plus skills, commands, agents, hooks, and the runbook protocol. The review process follows the two-stage structure (spec compliance, then code quality) with automated fixer dispatch.

Claude Code + companion plugins: Everything above, plus axiom's 7 backend dimensions and impeccable's design quality checks. Plugin findings merge with native findings before verdict computation. All plugin findings are informational and do not add new blocking gates.