Architecture

The plugin is written in Rust using nvim-oxi for typed bindings to Neovim's C API. The codebase is split into two crates:

arbiter-core

Pure-logic library with no Neovim dependency. All domain types, configuration, prompt formatting, diff parsing, thread data model, persistence, and revision building live here. This crate is testable on any platform without a Neovim runtime.

Module	Purpose
types	Shared domain types (review status, thread status, backend ops)
config	Configuration deserialization with per-workspace overrides
diff	Unified diff parser, hunk extraction, and patch building
threads	Thread CRUD, anchoring, filtering, and projection
prompts	Prompt formatting for reviews, replies, self-review, and rule extraction
rules	Scenario-scoped rule system with glob matching and TOML frontmatter
state	JSON persistence of review state, threads, and sessions
revision	Revision snapshot building and unified diff generation

arbiter

cdylib plugin loaded by Neovim. Contains all UI code, nvim-oxi bindings, and process management. Depends on arbiter-core for domain logic.

Module	Purpose
backend/	CLI adapter shim (Cursor, Claude) with FIFO queue, streaming, and process lifecycle
review/	Review workbench: lifecycle, keymaps, navigation, hunk acceptance, thread UI, and revision view
commands/	User command registration and self-review orchestration
diff/render	Diff buffer rendering and syntax highlighting
file_panel/	File panel implementations (builtin tree, nvim-tree adapter)
prompt_panel	Long-lived prompt conversations in a floating window
panel	Shared rendering utilities (timestamps, streaming, status lines)
dispatch	Safe cross-thread callback dispatch via libuv::AsyncHandle
git	Async git operations (merge-base, diff, show, stash) and staging/unstaging
poll	Periodic file and file-list refresh via libuv timers
activity	Backend busy/idle tracking for statusline display
highlight	Custom highlight groups and sign definitions