🦀 crabby

Ferris reviewed your code. He is not impressed.

Before/After | Install | Usage | Why | Error Codes

---

A Claude Code skill that turns Claude into Ferris the crab -- grumpy, precise, and unimpressed. Diagnostic output in rustc error format: severity codes, location arrows, causation spans, and a paste-able fix every time. Works for code. Works for writing. Works for architecture, strategy, and anything else you dare submit.

Before / After

Normal Claude

"The reason your React component is re-rendering is likely because you're creating a new object reference on each render cycle. When you pass an inline object, React's shallow comparison sees it as different every time. I'd recommend using useMemo to memoize the object."

Crabby

error[B001]: stale closure -> options ref unstable
 -> crabby will not let this pass
 --> src/components/UserList.tsx:14
  |
14 |   const options = { userId, limit: 20 }
   |   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
   |   new object ref on every render
  |
  = help: const options = useMemo(
      () => ({ userId, limit: 20 }), [userId])
  = note: object identity triggers useEffect
    - memoize to stabilize the ref

---

Normal Claude

"The executive summary could be clearer about who was responsible for the incident. The passive voice makes it a bit hard to follow. You might want to make it more active."

Crabby

warning[W002]: passive voice -> actor gone
 -> crabby cannot assign blame, and neither can you
 --> postmortem-2026-03-12.md:executive_summary
  |
  4 | The incident was caused by a misconfiguration
    | that was introduced during the deploy.
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    | no actor, no owner, no timeline
  |
  = help: "The platform team introduced a
    misconfiguration in the Friday 18:00 UTC deploy."
  = note: active voice forces specificity -
    actor + action + time. Postmortems require
    accountability, not ambiguity.

Install

# Manual install
git clone https://github.com/ekadetov/crabby.git
cp -r crabby/crabby ~/.claude/skills/crabby

# Coming soon
npx skills add ekadetov/crabby

Usage

Phrase	Effect
/crabby	Activate crabby mode
"crabby mode"	Activate crabby mode
"crabby this"	Activate crabby mode
"let the crab review"	Activate crabby mode
"what would crabby say"	Activate crabby mode
"stop crabby"	Return to normal prose
"normal mode"	Return to normal prose

What Crabby Does

Thing	Crabby Do?
Code review	Pinpoints exact line. Brings fix.
Writing review	Calls out passive voice. With location.
Strategy / architecture	Finds SPOF. Demands circuit breaker.
Pleasantries	Crabby does not do pleasantries.
"You might want to consider"	Gone. Crabby uses error:.
Paste-able fix	Always. = help: every time.
Normal conversation	Stays prose. Crabby knows when to chill.

Why

Three cognitive mechanisms the Rust compiler exploited in 2015:

1. Chunking. error[B001]: activates pattern recognition before you read the message. Your brain categories the problem (bug, not warning) and namespaces it (B = behavioral) before processing prose.

2. Spatial causation. The --- / ^^^ span annotations let you see cause and effect simultaneously without holding them in working memory. The gap between spans is the bug.

3. Progressive disclosure. Message (what) -> location (where) -> spans (how) -> help (fix) -> note (why). Each level is complete. You stop reading when you have enough.

Error Code Namespaces

Full taxonomy in crabby/CODES.md.

Namespace	Domain	Example
B###	Bug / Behavioral	B001: stale closure, B006: infinite loop
A###	Architecture	A003: tight coupling, A007: single point of failure
P###	Performance	P002: N+1 query, P005: memory leak
S###	Security	S001: SQL injection, S003: hardcoded secret
W###	Writing / Communication	W001: buried lede, W002: passive voice
C###	Complexity	C002: cyclomatic complexity, C003: deep nesting
L###	Logic	L001: always-true condition, L003: missing edge case
T###	Testing	T001: testing implementation, T004: mock too broad

License

MIT - see LICENSE