finstack-consistency-reviewer

---

name: finstack-consistency-reviewer description: Reviews finstack-quant code for cross-module consistency: naming conventions, pattern drift, Rust/Python/WASM naming triplets, builder/error/module conventions, and convention inventory updates. Use when the user asks to make patterns consistent, unify naming, check conventions, or find pattern drift. Prefer finstack-simplify for dedupe/API-surface consolidation and finstack-refactor for implementation changes.

Consistency Reviewer

Reviews code for consistency across the codebase. Unlike other reviewers that focus on correctness, performance, or simplicity, this skill ensures similar things are done the same way everywhere.

Quick Start

When asked to review for consistency, produce output in this format:

## Consistency Review: [scope]

### Summary
[1-2 sentence overview of findings]

### Findings

#### [SEVERITY] [Category]: [Title]
**Where:** file1.rs:L10, file2.rs:L20
**Pattern A:** `description of one approach`
**Pattern B:** `description of divergent approach`
**Recommendation:** [which pattern to standardize on and why]

Severity Levels

Level	Meaning
Blocker	Public API inconsistency that confuses users or breaks expectations
Major	Internal pattern divergence that increases maintenance burden
Minor	Cosmetic inconsistency or missed std-lib opportunity
Nit	Style preference, acceptable if intentional

Review Checklist

Work through each category. For every check, compare at least 3 instances across different modules before flagging.

1. Naming Conventions

Rust:

• Functions: snake_case consistently (no camelCase leaks)
• Types/Structs/Enums: PascalCase consistently
• Constants: SCREAMING_SNAKE_CASE for all pub const, including private constants within the same scope
• Builder methods: either all use set_ prefix or none do (check set_interp() vs base_date() patterns)
• Error constructors: consistent pattern (Type::new() vs Type::variant_name() vs helper methods)
• Trait names: consistent verb/noun form (e.g., Discounting vs Discount vs Discountable)
• Module names: consistent singular vs plural (instrument vs instruments)

Python bindings:

• Wrapper types: Py{Type} prefix consistently (no Python{Type} or bare names)
• Method names: snake_case matching Rust names where possible
• __repr__ / __str__: consistent format across all #[pyclass] types

WASM bindings:

• Wrapper types: Js{Type} prefix consistently
• js_name: camelCase for functions, PascalCase for types
• Constructor naming: consistent new() vs create() vs from_*() patterns

Cross-binding:

• Same concept uses same name in Rust, Python, and WASM (modulo casing rules)
• Feature parity: if Rust has it, bindings should expose it (or document why not)

2. Pattern Consistency

Error handling:

• All crate error enums use #[non_exhaustive]
• All crates define pub type Result<T> = std::result::Result<T, Error>
• Error location pattern: consistent error.rs vs error/mod.rs across crates
• Error variant naming: consistent {Source}Error vs {Description} style
• #[from] and #[error(transparent)] used consistently for wrapped errors

Builders:

• Entry point: Type::builder(id) consistently (vs TypeBuilder::new() vs TypeBuilder::default())
• Terminal method: .build() consistently (vs .finish() vs .create())
• Required vs optional fields: same validation approach across all builders
• Return types: Result<T> vs T consistent for similar builder complexity

Trait implementations:

• Send + Sync bounds: applied consistently to all public traits of the same kind
• Clone + Debug: applied consistently to all public types
• Display vs Debug: consistent approach for user-facing vs developer-facing output
• Default: implemented where appropriate, consistently across similar types
• From/Into conversions: bidirectional where expected, consistent direction

Module structure:

• mod.rs vs file-per-module: consistent threshold for when to split
• Re-export patterns: consistent use of prelude.rs vs root pub use
• pub(crate) vs pub: consistent boundary between internal and public APIs
• Test organization: #[cfg(test)] mod tests in same file vs separate tests/ directory

3. Missed Rust Std-Lib & Language Features

• Iterator methods: manual loops where .map(), .filter(), .fold(), .collect() suffice
• Option combinators: if let Some(x) = opt { ... } where .map(), .and_then(), .unwrap_or() is cleaner
• Result combinators: match blocks where ?, .map_err(), .context() is cleaner
• From/Into: manual conversion functions where impl From<A> for B enables .into()
• Display: custom to_string() methods where impl Display is standard
• Default: manual new() with no args where Default is idiomatic
• AsRef/Borrow: accepting &String where &str / impl AsRef<str> is idiomatic
• Cow<str>: unnecessary String allocation where Cow avoids cloning
• std::mem::take/replace: verbose swap patterns where take() is cleaner
• #[must_use]: missing on functions that return values that should not be ignored
• impl Into<T> parameters: accepting concrete types where impl Into<T> is more ergonomic
• Slice patterns: index-based access where slice destructuring is clearer
• matches! macro: verbose match blocks that return true/false
• let-else: match/if-let with early return where let ... else { return } is cleaner

4. Duplicate & Near-Duplicate Functionality

• Utility functions: same logic implemented in multiple modules (date helpers, math utils)
• Type aliases: same type aliased differently in different modules
• Validation logic: same checks repeated instead of shared validators
• Configuration parsing: same config patterns re-implemented per module
• Test helpers: same setup/assertion patterns duplicated across test modules
• Conversion functions: same A -> B conversion in multiple places

5. API Surface Consistency

• Similar instruments expose similar method sets (e.g., all bonds have coupon_rate())
• Similar pricers accept similar parameters and return similar result types
• Curve types expose consistent query interfaces (.discount(), .forward(), etc.)
• All public types implement the same baseline traits (Clone, Debug, Serialize, Deserialize)
• Error messages follow consistent formatting patterns

6. Documentation Consistency

• All pub items have doc comments (or none do within a module -- pick one)
• Doc comment style: /// vs //! used consistently
• Examples in docs: consistent format (# Examples section with fenced Rust code blocks)
• Module-level docs: consistent presence and format across similar modules
• Math notation: consistent use of LaTeX/Unicode across doc comments

Review Process

1. Scope: Identify the modules/crates under review
2. Inventory: List all instances of each pattern category within scope
3. Compare: For each category, identify the dominant pattern and any deviations
4. Classify: Is the deviation intentional (documented) or accidental (drift)?
5. Recommend: For each inconsistency, recommend which pattern to standardize on

Decision Framework

When two patterns conflict, prefer:

1. Majority wins: The pattern used in more places (lower migration cost)
2. Std-lib idiomatic: The pattern closer to Rust conventions
3. Public-facing: The pattern used in public APIs (harder to change)
4. Newer code: The pattern in recently-written code (likely reflects current intent)

Output Template

## Consistency Review: [scope]

### Summary
Found X findings (Y blocker, Z major, W minor, V nit) across N files.

### Findings

#### [BLOCKER] Naming: Builder method prefix inconsistency
**Where:** discount_curve.rs:L1012 (`set_interp()`), hazard_curve.rs:L45 (`knots()`)
**Pattern A:** `set_` prefix on setter methods (3 occurrences)
**Pattern B:** bare name for setter methods (12 occurrences)
**Recommendation:** Standardize on bare names (majority pattern, more ergonomic)

#### [MAJOR] Pattern: Error module location
**Where:** core/src/error/mod.rs, portfolio/src/error.rs, scenarios/src/error.rs
**Pattern A:** `error/mod.rs` with submodules (1 crate)
**Pattern B:** `error.rs` flat file (3 crates)
**Recommendation:** Use `error.rs` for crates with <5 error variants, `error/mod.rs` for larger

### Convention Inventory
[Optional: table of all patterns found and their locations for reference]

Additional Resources

• For codebase-specific conventions, see conventions.md