# 097 Index 1c9230a4

> Module Documentation

- Skill: `tools-only/097-index-1c9230a4` (Agent Skill, multi-file: 3 files)
- Install (CLI): `npx skillmds@latest add tools-only/097-index-1c9230a4`
- Raw SKILL.md: https://api.skillmd.com/api/skills/tools-only/097-index-1c9230a4/raw
- Safety review: pending
- Works with: Claude Code, Claude.ai, OpenAI Codex
- Category: Docs & Writing
- Author: tools-only (https://skillmd.com/u/tools-only)
- Updated: 2026-09-22
- Page: https://skillmd.com/skills/tools-only/097-index-1c9230a4

---


# Module Documentation

TunaCode is structured in seven layers. Dependencies flow downward only.

```
ui              Textual TUI, widgets, renderers, screens
  |
core            Agent loop, compaction, session, logging, state machine
  |
tools           Tool implementations exposed to the LLM
  |
configuration   Settings, model registry, paths, limits, pricing
  |
infrastructure  Cache manager, invalidation strategies, named caches
  |
utils           Message conversion, token estimation, gitignore file listing
  |
types           Base aliases, callback protocols, canonical message model
```

## Reading Order

Start from the bottom if you need to understand the type system.
Start from the top if you need to change the UI.
Start from `core/core.md` if you need to understand how a user prompt becomes an LLM response.

| Layer           | Document                                 | Key concern                          |
|-----------------|------------------------------------------|--------------------------------------|
| types           | [types/types.md](types/types.md)                     | Aliases, protocols, canonical model  |
| utils           | [utils/utils.md](utils/utils.md)                     | Message adapter, token estimation    |
| infrastructure  | [infrastructure/infrastructure.md](infrastructure/infrastructure.md)   | Thread-safe caching                  |
| configuration   | [configuration/configuration.md](configuration/configuration.md)     | User config, model registry          |
| tools           | [tools/tools.md](tools/tools.md)                     | LLM-callable tool implementations    |
| core            | [core/core.md](core/core.md)                       | Agent loop, compaction, session      |
| ui              | [ui/ui.md](ui/ui.md)                           | Textual app, widgets, theming        |

## Root-Level Files

These files live directly under `src/tunacode/` and do not belong to any sub-package.

| File              | Purpose                                                         |
|-------------------|-----------------------------------------------------------------|
| `__init__.py`     | Package marker (empty).                                         |
| `constants.py`    | Global constants: version, color palettes, theme builders, tool names, UI sizing. |
| `exceptions.py`   | Exception hierarchy rooted at `TunaCodeError`. Every custom exception lives here. |