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<img src="https://raw.githubusercontent.com/breferrari/vigia/main/assets/banner.jpg" alt="vigia: a watchtower sweeping a beam of light across changed lines of code" width="100%">
### The terminal pane your **coding agent** works beside.
*Portuguese: a watchman, the one who keeps watch. At sea, also a porthole.*
[](https://crates.io/crates/vigia) [](https://crates.io/crates/vigia) [](https://github.com/breferrari/vigia/actions/workflows/ci.yml) [](https://github.com/breferrari/vigia/blob/main/LICENSE) [](https://crates.io/crates/vigia)
**Your agent writes in one pane. `vigia` watches in the pane beside it, and carries your words back.**
It shows the working-tree diff live, as the agent writes it. Click a line, type one sentence, and it goes to the agent that wrote that line.
`< 50 ms` to first paint · `60 fps` while files are being written · `0` wakeups while idle · legible at `40` columns · pure Rust, on macOS · Linux · Windows
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<img src="https://raw.githubusercontent.com/breferrari/vigia/main/assets/preview.svg" alt="The vigia interface: a pinned list of changed files, each row carrying a caret, a status letter, a path, a note mark, a change sparkline, a heat strip and line counts, above a syntax highlighted diff whose own file heading repeats the same row, with a note box open under a changed line holding a half-typed sentence for the agent, a scrollbar down its side and a status bar showing key hints, frame time, resident memory and the follow state." width="100%">
---
## 🔭 Why
**This is not a diff viewer you open.** A diff viewer shows *what changed* once, when you ask. A coding agent edits **fast**, across **many files**, often while you are reading something else. Its scrollback tells you what it *said* it did, not what actually changed on disk.
`vigia` shows what actually changed, continuously, without you touching it. It also sends a sentence from you back to the agent, tied to the line you were looking at. One pane writes. One pane watches, and answers.
| | |
|---|---|
| 🤖 **For the pane beside the agent** | Zero input. It follows the newest change and scrolls to it on its own |
| ✍️ **Talk back to a line** | Click a line number, type, `Enter`. Your agent gets the file, the line and your words |
| 🖼️ **Pictures, not bytes** | A changed image, SVG or PDF shows its old and new pictures side by side |
| 🕰️ **Look back without leaving** | `B` stands the pane anywhere in the branch's history, and back |
| 🪶 **Cheap enough to leave open for a week** | Zero wakeups while idle. Under 5% memory drift over 24 hours |
| 📐 **Fits half a laptop screen** | Legible at 40 columns, because that is the actual pane you have |
| ⌨️ **Nothing to learn first** | `?` draws every gesture, `m` every on/off setting. `~/.config/vigia/config` decides what it opens as |
> [!NOTE]
> **A monitor, not a reviewer.** It can browse history and send your notes to the agent, but it asks nothing of you. A reviewer is something you launch, work through and finish. `vigia` is already open, correct before you touch it, and still correct if you never do.
## ⏱️ Try it in 30 seconds
```sh
brew install breferrari/tap/vigia # macOS and Linux
vigia # in the pane beside your agent, inside a repo
claude mcp add --scope user vigia -- vigia mcp # optional: notes for Claude Code
```
No Homebrew, or on Windows? [Install](#install) has a prebuilt installer for each.
---
<a id="talk-back"></a>
## ✍️ Talk back to the line
You see a line you want changed. Click its line number, type one sentence, press `Enter`.
```
40 + self.deadline = Instant::now() + DEBOUNCE;
✎ should this reset on every event, or just the first?
```
1. **The pane writes the note first.** Each note is a file in a directory kept for this worktree under your state directory, never inside the worktree or `.git`. So a note survives a restart of the pane or the agent, and two repositories never see each other's notes.
2. **Then it hands the note to the agent.** The footer says `sent` when a registered agent session took it, and `noted` when none did and the note is waiting for the agent to look. `sent` means the session took the line. It does not mean the agent has read it. If the agent is waiting on a permission prompt, the note queues and is handled once you answer (observed 2026-10-20 with Claude Code 2.1.304 on macOS).
3. **The agent gets the file, the line, your words and the code around it**, as plain text:
```
vigia note on src/engine/watch.rs:40
should this reset on every event, or just the first?
37 | }
38 | fn coalesce(&mut self, ev: Event) -> Option<Frame> {
39 | if self.pending.is_empty() {
> 40 | self.deadline = Instant::now() + DEBOUNCE;
41 | }
42 | self.pending.push(ev);
43 | None
Act on it, then resolve it with the vigia MCP server: resolve(id: "65e47ff14944b-79fa-0", note: "<one line: what you did, or why you declined>"). Ask only if the note is unclear, and ask here, with options: the pane cannot answer.
```
4. **The agent fixes the line and resolves the note** with one line saying what it did. That line appears under your note, and then the note leaves. If it declines the note, it resolves it with the reason. If the note is unclear, it asks you in its own session, because you cannot answer in the pane.
`vigia` calls no model, summarises nothing and judges nothing. It carries your words, and the agent answers.
**How it reaches the agent.** `vigia mcp` is an MCP server with three tools, `notes`, `reply` and `resolve`. Hooks do the rest: `vigia mcp register` records a running Claude Code session so `Enter` can post the note straight into it, and `vigia mcp pending` puts one line in front of your next prompt when a note is waiting.
| | MCP server | Posted into a running session | Line before your next prompt |
|---|---|---|---|
| **Claude Code** | yes | yes | yes |
| **Any other MCP client** (Codex, for one) | yes | no | yes, with a prompt hook |
Without the live post, a note waits until the agent next calls `notes` or you send your next prompt.
**How fast.** From `Enter` to the note arriving on the session's socket. Measured 2026-10-20: 3.4 ms at the median and 21 ms at the slowest, over 32 notes on an Apple M1 Max with a release build ([how](https://github.com/breferrari/vigia/blob/main/docs/NOTES.md#how-fast-a-note-leaves)). How soon the agent acts on it after that is up to the agent.
**Set it up once**, for every project you open:
```sh
claude mcp add --scope user vigia -- vigia mcp
```
Then add the three hooks to `~/.claude/settings.json`. [**Notes to the agent**](https://github.com/breferrari/vigia/blob/main/docs/NOTES.md) has the hooks, what each note state means, other agents, and the small print.
---
<a id="install"></a>
## 🚀 Install
Homebrew, on macOS and Linux:
```sh
brew install breferrari/tap/vigia
```
A prebuilt binary, with no toolchain at all:
```sh
# macOS and Linux
curl --proto '=https' --tlsv1.2 -LsSf https://github.com/breferrari/vigia/releases/latest/download/vigia-installer.sh | sh
# Windows
powershell -ExecutionPolicy Bypass -c "irm https://github.com/breferrari/vigia/releases/latest/download/vigia-installer.ps1 | iex"
```
From source, with a Rust toolchain: `cargo install vigia`.
[**Installing**](https://github.com/breferrari/vigia/blob/main/docs/INSTALL.md) covers the release archives, checking a download, and upgrading on Windows while an agent session is open.
## 🧭 Your first five minutes
1. **Point it at a repo.** `vigia` watches the tree you are in, or `vigia ~/code/some-repo`. Leave it in the pane beside your agent. There is nothing to configure and nothing to press.
2. **Let it follow.** As your agent writes, files appear in the pinned list at the top and the diff scrolls to whatever landed last. The sparkline says *when*, the heat strip says *where in the file*, the counters say *how much*.
3. **Say something about a line.** Click a line number, type, `Enter`, as in [Talk back to the line](#talk-back).
4. **Look back when you need to.** `B` lists every place the pane can stand: the live tree, the branch point, or any commit behind it. `Esc` and you are back.
5. **Forget the rest.** `?` puts every gesture on screen, and `m` every on/off setting.
---
## 👀 What you see
Each row answers one question: the caret says where you are, the pulse `●` which file was written last, the note mark whose turn it is, the heat strip **where** in the file the change is, the sparkline **when** it changed, and the counters **how much**. The diff is syntax highlighted, and the words that changed inside a line are lit brighter than the line around them.
**A changed picture shows as pictures**. A changed image, SVG or PDF draws its old and new versions side by side, with the changed pixels marked. Terminals that draw Kitty graphics, Sixel or iTerm2 images (kitty, Ghostty, iTerm2, WezTerm, foot, Windows Terminal) draw them sharp. Everywhere else they draw in half-blocks, which need 24-bit colour.
[**Reading the pane**](https://github.com/breferrari/vigia/blob/main/docs/READING.md) explains every signal, how a file finds its language, and what the pane never selects.
## ⌨️ Keys
**Keys**
| | |
|---|---|
| `j` `k` `↑` `↓` | scroll a row |
| `n` `p` `→` `←` | next / previous file |
| `f` | follow the newest change, or stop |
| `s` | one file, or the whole diff |
| `a` | show or hide staged changes |
| `B` | everywhere else it can stand |
| `Ctrl+L` | redraw, and send pictures again after a tmux reattach |
| `?` `Esc` | every gesture, on screen |
| `q` `Ctrl+C` | quit |
The mouse works too: the wheel scrolls what you point at, a click on a file jumps to it, and dragging the diff copies those rows. [**Keys and mouse**](https://github.com/breferrari/vigia/blob/main/docs/KEYS.md) has every key and gesture.
---
## ⚡ Promises
Budgets, not hopes. Each one has a test that fails when it is missed. Every regression **fails the build** except memory drift, which a scheduled soak checks.
| | | |
|---|---|---|
| 🔔 | **Event driven** | Zero wakeups while idle. No filesystem event, no work. Never a polling timer |
| 🚀 | **Instant start** | Under 50ms to first paint |
| 🌊 | **Streaming** | First paint under 100ms, even on a 100,000 line diff |
| 🎞️ | **60fps** | Frame time under 16ms at p99, *while files are being written* |
| ♻️ | **Incremental diff** | Re-diff cost scales with what changed, not with your worktree |
| 🖍️ | **Incremental highlight** | Re-parse cost scales with your edit, not the file |
| 🪶 | **Flat over days** | Under 5% memory drift across 24 hours. No retained temp files |
| 🧘 | **Correct untouched** | Follows the newest change and scrolls to it with no input |
| 📐 | **Narrow panes** | Legible at 40 columns |
| 🚪 | **Clean exit** | Terminal restored on every exit it can observe: the quit key, `Ctrl+C`, an error, a panic, or the first kill from outside |
## 🎨 Make it yours
**It matches your terminal out of the box.** At startup `vigia` asks your terminal whether its background is dark or light and picks the matching palette. There is nothing to set up.
**To make it yours, write a theme file** at `~/.config/vigia/theme`. Start from a built-in palette (`dark`, `light` or `ansi`) and change only what you want:
```ini
base = dark
added = #3fb950
removed = #f85149
```
It is read every time the pane starts. [**Theme**](https://github.com/breferrari/vigia/blob/main/docs/THEME.md) lists every colour you can set.
**Settings** (staged changes, wrapping, the note rows, what the pane opens as) live in `~/.config/vigia/config`. Press `m` in the pane to switch them, and with `persist` on your choices are written back to that file.
For a single run, `VIGIA_THEME` and `NO_COLOR` still work, and so do `VIGIA_PICTURES` for how pictures are drawn and `VIGIA_UPDATE=off` for the update check. [**Configuration**](https://github.com/breferrari/vigia/blob/main/docs/CONFIG.md) covers them.
---
## 📚 Documentation
| | |
|---|---|
| [Notes to the agent](https://github.com/breferrari/vigia/blob/main/docs/NOTES.md) | Setting up notes, what each state means, other agents |
| [Reading the pane](https://github.com/breferrari/vigia/blob/main/docs/READING.md) | Every signal on screen, highlighting, changes inside a line |
| [Keys and mouse](https://github.com/breferrari/vigia/blob/main/docs/KEYS.md) | Every key and gesture, and the small print |
| [Installing](https://github.com/breferrari/vigia/blob/main/docs/INSTALL.md) | Every install path, checking a download, upgrading on Windows |
| [Configuration](https://github.com/breferrari/vigia/blob/main/docs/CONFIG.md) | The config file, its keys, colour depth, glyphs and themes |
| [Theme](https://github.com/breferrari/vigia/blob/main/docs/THEME.md) | Every colour the pane draws |
| [Built with](https://github.com/breferrari/vigia/blob/main/docs/ARCHITECTURE.md) | The dependencies, what each one does, and the numbers behind the promises |
| [mcs pack](https://github.com/breferrari/vigia/blob/main/docs/TECHPACK.md) | Installing the notes setup with `mcs` |
These pages track `main`. For a released version, browse its tag.
**About the picture at the top.** It is a mockup drawn with `VIGIA_THEME=dark`, not a screenshot, and everything in it draws in the real pane. One difference: the real header shows your worktree's name where the picture says `vigia`.
## ❓ Questions
**Does it change my repository?** No. It writes nothing into the worktree and nothing into `.git`. Your notes live in a directory for this worktree under your state directory.
**Does it need an agent?** No. It is a live diff on its own. An agent is only needed to receive your notes.
**Does it go online?** Once per start, to ask crates.io whether a newer release exists. `VIGIA_UPDATE=off` turns that off. Nothing else leaves the machine.
**Does it need git-lfs?** No. The pane never starts `git-lfs`, and it reads an LFS image from the local LFS store.
**Does it work on Windows?** Yes. Use the PowerShell installer above. Windows Terminal 1.22 and later draws pictures sharp.
**Which terminals draw sharp pictures?**
| Pictures | Terminals |
|---|---|
| Sharp | kitty, Ghostty, iTerm2, WezTerm, Rio, foot, Windows Terminal 1.22 and later, xterm with Sixel on |
| Half-blocks | Warp, and everything else, given 24-bit colour |
Inside tmux the picture passes through to the terminal outside it.
## 🗺️ Status
Released, and built in the open, spec first. [`ROADMAP.md`](https://github.com/breferrari/vigia/blob/main/ROADMAP.md) is the live plan, [`SPEC.md`](https://github.com/breferrari/vigia/blob/main/SPEC.md) the contract it is built against, and [`CHANGELOG.md`](https://github.com/breferrari/vigia/blob/main/CHANGELOG.md) every released version.
## 🏷️ The name
*Vigia* is Portuguese: a watchman, a lookout, the one who keeps watch. At sea it also means a porthole, the small round window you look through.
Both readings are the tool. It watches, and it is the window you watch through.
It is also the verb, third person. So `vigia .` reads as a sentence.
## 🤝 Contributing
Issues and pull requests are welcome, and a plain bug report needs two lines: what you expected, what happened. [`CONTRIBUTING.md`](https://github.com/breferrari/vigia/blob/main/CONTRIBUTING.md) has the rest, including the one real ask: `SPEC.md` is read before code. Some things this project will not do, such as staging, committing and rebasing, AI features of its own, git remote operations, or a GUI. [`ROADMAP.md`](https://github.com/breferrari/vigia/blob/main/ROADMAP.md#non-goals-permanent) lists them.
---
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**MIT** · Built in the open · [SPEC](https://github.com/breferrari/vigia/blob/main/SPEC.md) · [ROADMAP](https://github.com/breferrari/vigia/blob/main/ROADMAP.md) · [CHANGELOG](https://github.com/breferrari/vigia/blob/main/CHANGELOG.md) · [Issues](https://github.com/breferrari/vigia/issues)
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