m11-ecosystem

SKILL.md

Current Dependencies (Auto-Injected)

!grep -A 100 '^\[dependencies\]' Cargo.toml 2>/dev/null | head -30 || echo "No Cargo.toml found"

Ecosystem Integration

Layer 2: Design Choices

Core Question

What's the right crate for this job, and how should it integrate?

Before adding dependencies:

Is there a standard solution?

What's the maintenance status?

What's the API stability?

Integration Decision → Implementation

Need
Choice
Crates

Serialization
Derive-based
serde, serde_json

Async runtime
tokio or async-std
tokio (most popular)

HTTP client
Ergonomic
reqwest

HTTP server
Modern
axum, actix-web

Database
SQL or ORM
sqlx, diesel

CLI parsing
Derive-based
clap

Error handling
App vs lib
anyhow, thiserror

Logging
Facade
tracing, log

Thinking Prompt

Before adding a dependency:

Is it well-maintained?

Recent commits?

Active issue response?

Breaking changes frequency?

What's the scope?

Do you need the full crate or just a feature?

Can feature flags reduce bloat?

How does it integrate?

Trait-based or concrete types?

Sync or async?

What bounds does it require?

Trace Up ↑

To domain constraints (Layer 3):

"Which HTTP framework should I use?"
    ↑ Ask: What are the performance requirements?
    ↑ Check: domain-web (latency, throughput needs)
    ↑ Check: Team expertise (familiarity with framework)

Question
Trace To
Ask

Framework choice
domain-*
What constraints matter?

Library vs build
domain-*
What's the deployment model?

API design
domain-*
Who are the consumers?

Trace Down ↓

To implementation (Layer 1):

"Integrate external crate"
    ↓ m04-zero-cost: Trait bounds and generics
    ↓ m06-error-handling: Error type compatibility

"FFI integration"
    ↓ unsafe-checker: Safety requirements
    ↓ m12-lifecycle: Resource cleanup

Quick Reference

Language Interop

Integration
Crate/Tool
Use Case

C/C++ → Rust
bindgen
Auto-generate bindings

Rust → C
cbindgen
Export C headers

Python ↔ Rust
pyo3
Python extensions

Node.js ↔ Rust
napi-rs
Node addons

WebAssembly
wasm-bindgen
Browser/WASI

Cargo Features

Feature
Purpose

[features]
Optional functionality

default = [...]
Default features

feature = "serde"
Conditional deps

[workspace]
Multi-crate projects

Error Code Reference

Error
Cause
Fix

E0433
Can't find crate
Add to Cargo.toml

E0603
Private item
Check crate docs

Feature not enabled
Optional feature
Enable in features

Version conflict
Incompatible deps
cargo update or pin

Duplicate types
Different crate versions
Unify in workspace

Crate Selection Criteria

Criterion
Good Sign
Warning Sign

Maintenance
Recent commits
Years inactive

Community
Active issues/PRs
No response

Documentation
Examples, API docs
Minimal docs

Stability
Semantic versioning
Frequent breaking

Dependencies
Minimal, well-known
Heavy, obscure

Anti-Patterns

Anti-Pattern
Why Bad
Better

extern crate
Outdated (2018+)
Just use

#[macro_use]
Global pollution
Explicit import

Wildcard deps *
Unpredictable
Specific versions

Too many deps
Supply chain risk
Evaluate necessity

Vendoring everything
Maintenance burden
Trust crates.io

Related Skills

When
See

Error type design
m06-error-handling

Trait integration
m04-zero-cost

FFI safety
unsafe-checker

Resource management
m12-lifecycle