thetonymaster/composition-software-engineering

A Claude Code plugin marketplace with one plugin, principles: five skills
that steer how Claude designs, refactors and reviews code, and one agent that
audits code against them.
| Skill | Use it when |
| composition | reaching for an abstraction, a base class, a mixin, embedding or use; deciding whether an abstraction earns its keep |
| dependency-injection | code hardcodes a client, global, disk, network or clock; tests need monkeypatching; one function branches per backend |
| flat-code | a function nests past depth 3, chains if/else, or has an else after return |
| measure-first | someone says "make it faster", "optimize" or "is X faster than Y", before trading readability for speed |
| principles-audit | auditing a diff or module against the four principles above, or briefing a subagent to work under them |
| Agent | Use it when |
| principles-auditor | you want a principles-audit report from a fresh context that did not write the code; it reads and runs checks, and does not edit |
Every skill has references for Go, Python, Elixir, TypeScript, Java, Rust
and C# (references/ .md), loaded only when the code under review
is in that language. flat-code ships scripts/nestingdepth.py, which
measures nesting in all seven (Python exactly from the ast, the rest by an
indentation heuristic) and exits 2 on any other file type. Against exact
parsers the heuristic found 87/90 over-nested TypeScript functions and 59/60
Java methods; Rust and C# were spot-checked by hand.
## Install
From GitHub (needs access to this repository):
/plugin marketplace add thetonymaster/composition-software-engineering
/plugin install principles@composition-software-engineering
From a local clone:
/plugin marketplace add /path/to/composition-software-engineering
/plugin install principles@composition-software-engineering
Skills are namespaced once installed: principles:composition,
principles:flat-code, and so on. They trigger from their descriptions; you
can also invoke one by name, e.g. /principles:principles-audit. The agent
is principles:principles-auditor; ask Claude to "run the principles-auditor
agent on this branch", or pick it from /agents.
## How much of the reference material was executed
| Language | Snippets | Tool names, flags, rule IDs |
| Go | key claims probed (embedding, nil interface, b.Loop benchmark); not every snippet run | audit greps run on a real repo |
| Python | not executed | reviewed; profiling.sampling CLI checked |
| Elixir | not executed (Benchee example not run) | reviewed |