V3 deterministic Python lint and format-check capability pack. By-value connector composition (service_kind=cli, no separate ingredient): one local ruff CLI ingredient exposes bounded project operations for readiness, lint diagnostics, and format-check diagnostics. Checks run from an explicit project directory cwd supplied at execution time, inspect one trusted local Python file or project path, and return JSON diagnostics via python.lint and python.format_check catalog operations. Fixed-function and reproducible: no arbitrary ruff flags, no fixing/writing mode, no caller-supplied config path, no shell wrapper, and no network egress. Lint or formatting findings are represented as JSON output instead of failing the op; real invocation errors still fail. Requires ruff on PATH (Python environments: pip install ruff; macOS: brew install ruff). Local and no-egress.