manual_slop/conductor/code_styleguides/python.md

# AI-Optimized Python Style Guide

This document defines the Python style conventions for the Manual Slop codebase.
These deviate from PEP 8 / Google style to minimize token consumption when code
is processed by AI agents, while preserving readability for human review.

## 1. Indentation and Whitespace

- **Indentation:** 1 space per level. No tabs.
- **Continuation lines:** 1 space relative to the opening construct.
- **Blank lines:** Zero blank lines between function/method definitions within a class. One blank line between top-level definitions only when separating logically distinct sections.
- **Trailing whitespace:** None.
- **Rationale:** 1-space indentation reduces token count by ~40% compared to 4-space on deeply nested GUI code, with no loss of structural clarity for AST-based tools.

### Maximum Nesting Depth

- **Hard limit: 5 levels maximum.**
- AI agents consistently misinterpret Python scope via indentation. This hard limit prevents deeply nested blocks that confuse model interpretation.
- Classes and async handlers typically consume 1-2 levels before business logic begins, so 5 accommodates real-world usage patterns.
- **Enforcement:** Use ruff `[tool.ruff.lint.mccabe] max-complexity = 5` in the project linter config.
- **Refactoring mandate:** Any block exceeding 5 levels must be extracted into a named function. Do not "work around" this with tricks—extract the logic.
- **Rationale:** GUI callbacks and async handlers naturally want to nest. This constraint forces extraction of deep logic into testable, named units.

## 2. Type Annotations

- **All functions and methods** must have return type annotations.
- **All parameters** (except `self`/`cls`) must have type annotations.
- **Module-level and class-level variables** must have type annotations.
- **Use modern syntax:** `list[str]`, `dict[str, Any]`, `X | None` over `Optional[X]` where Python 3.10+ is available. Use `from __future__ import annotations` if needed.
- **Callable:** Use bare `Callable` for callback factories. Use `Callable[[ArgTypes], ReturnType]` when the signature is known and stable.
- **DearPyGui / ImGui callbacks:** Use `sender: Any, app_data: Any` for framework callbacks where the types are runtime-determined.

## 3. Imports

- Use `from __future__ import annotations` at the top of every module.
- Group imports: stdlib, third-party, local — separated by a blank line.
- Use `from typing import Any, Optional, Callable` etc. for type-only imports.
- Prefer `from x import Y` for specific symbols over `import x` when only one or two names are used.

## 4. Naming

- **snake_case** for modules, functions, methods, variables.
- **PascalCase** for classes.
- **ALL_CAPS** for module-level constants.
- **Single leading underscore** (`_name`) for internal/private members.

## 5. Docstrings

- Required on classes and non-trivial public functions.
- Use `"""triple double quotes"""`.
- One-line summary is sufficient for simple methods.
- Omit docstrings on obvious internal methods (e.g., `_cb_*` callbacks, `_render_*` UI methods) where the name is self-documenting.

## 6. String Formatting
- Prefer f-strings.
- Use double quotes (`"`) for strings by default.
- Use single quotes when the string contains double quotes.

## 7. Error Handling
- Never use bare `except:`.
- Use specific exception types.
- Prefer `if x is None:` over `if not x:` when testing for None specifically.

## 8. AI-Agent Specific Conventions

- **No redundant comments.** Do not add comments that restate what the code does. Only comment on *why* when non-obvious.
- **No empty `__init__.py` files.**
- **Minimal blank lines.** Token-efficient density is preferred over visual padding.
- **Short variable names are acceptable** in tight scopes (loop vars, lambdas). Use descriptive names for module-level and class attributes.

## 10. Anti-OOP Conventions

### Philosophy
AI agents consistently misinterpret class hierarchies, method resolution, and inheritance. Flat function-call graphs are deterministic and traceable. OOP introduces scoping complexity that compounds with indentation.

### Hard Rules (Enforced by lint)
- **Never write a class for a single method.** Use a function.
- **Never use inheritance for code reuse.** Compose with standalone functions.
- **Never use private methods (`_method`).** Module-level functions with clear names suffice.
- **No nested classes.** Define helper types at module level.
- **No decorator classes.** Use plain functions with decorators.

### Class Justification Required
Every class definition MUST include a comment explaining WHY it is a class and not a function group or struct:

```python
# JUSTIFIED: Holds mutable shared state across multiple async operations
# Cannot be replaced by functions without passing state through every call
class AsyncOperationScheduler:
    ...

# NOT JUSTIFIED: Simply groups related functions
# Should be module-level functions in operations.py
class OperationHelper:
    def validate(self): ...
    def execute(self): ...
```

### Acceptability Criteria
A class is justified ONLY when ALL of:
1. It holds mutable state that must be encapsulated
2. It has 3+ related methods that share state
3. It implements a behavioral interface used polymorphically (not just data grouping)

### Refactoring Existing Classes (Strangler Fig Pattern)
When refactoring a class to functions:
1. Write test validating current behavior (prevents regression)
2. Extract one method at a time into module-level functions
3. Create wrapper function that delegates to class until migration complete
4. Delete class only when ALL callers migrated
5. Commit with `refactor(oop):` prefix

### Data Structures
- **Data-only containers:** Use `NamedTuple`, `dataclass(frozen=True)`, or plain `dict` — NOT classes
- **State machines:** Use dict-based transitions, not class + inheritance
- **Configuration:** Plain dict or `TypedDict`, not classes with defaults

### Anti-Patterns (Flagged by Ruff PLR rules)
- `PLR0912`: Too many branches — extract to functions
- `PLR6301`: No public methods — class is a namespace anti-pattern
- `PLR0206`: Descriptors in class body — use simple attributes

### Enforcement
```toml
[tool.ruff.lint.select]
select = ["E", "F", "W", "C90", "C4", "PLR0912", "PLR6301", "PLR0206"]

[tool.ruff.lint.plr]
max-returns = 4
max-locals = 8
max-args = 5
```

## 11. Structural Dependency Mapping (SDM)

To assist AI agents in evaluating refactoring impact across dynamic codebases, all major definitions SHOULD include terse SDM tags at the end of their docstrings.

- **Format:** Tags are enclosed in square brackets at the end of the docstring body.
- **For Functions/Methods:** `[C: CallerA, CallerB]` — List of primary internal callers within the codebase.
- **For State Variables:**
  - `[M: File:Line, Method]` — List of primary mutation points (where the value is assigned).
  - `[U: File]` — Major codepaths of use (where the value is read but not changed).

### Example:
```python
def start_services(self) -> None:
 """
 Initialises background threads and MCP servers.
 [C: App.run, _cb_load_project]
 """
 ...
```