titah-extension-diff

Editor-style git diff panel for Titah. Line numbers, colours, and — the point of it — block a range of lines and send it to the main prompt.

Requires Titah with extension API ^0.5.0.

What it looks like

─ src/core/agent.ts ─────────────────────────────────
        ⋯ 4
  4  4      return load()
  5  5    }
  6  6
     7 ▌+ export function summarize(sep) {
     8 ▌+   return turns().map((t) => t.text).join(sep)
›    9 ▌+ }
    10  +
  7 11    export function count() {

VISUAL 3 lines · y send · v cancel

Press y and your prompt becomes @src/core/agent.ts:7-9 , with the cursor right after it. Type "add a doc comment for this function" and send.

Why a reference and not the diff text

What lands in the prompt is the address, not the code. The agent reads the file itself with the tools it already has, so blocking a hundred lines costs the same as blocking three — and the agent sees the file as it is now, not a snapshot that goes stale the moment anything else edits it.

Features

• Unified diff against HEAD — everything that differs from the last commit, staged or not, each hunk exactly once.
• Gutter with old/new line numbers, additions green, deletions red, file headers as section rules. The gutter hides itself on narrow panels: at the default 20-column width it would leave no room for the code. Widen with + and it comes back.
• Visual selection — v to anchor, ↑↓ to extend, y to send. y without a selection sends the line under the cursor.
• Click to move the cursor, and to extend a selection while visual mode is on.
• Refresh: r, plus automatic refresh on prompt send, turn end, and panel open.

Installation

{
  "extension": {
    "@titah/extension-diff": {
      "side": "right",
      "key": "<leader>d",
      "options": {
        "gitDiffLimit": 200,
        "contextLines": 3,
        "showWhitespace": false
      }
    }
  },
  // Worth widening: the gutter needs the room, and the default is 20.
  "panel": { "right": { "width": 64 } }
}

Options

| Option | Type | Default | Description | |--------|------|---------|-------------| | gitDiffLimit | number | 200 | Maximum diff lines to read | | contextLines | number | 3 | Context lines for git diff -U | | showWhitespace | boolean | false | false passes --ignore-space-change |

Keybindings

| Key | Action | |-----|--------| | ↑ / ↓ | Move the cursor; extend the selection when visual mode is on | | v | Start a selection, or cancel the one you have | | y | Send the selection (or the cursor line) to the prompt | | r | Manual refresh |

Esc is not a cancel key here — Titah intercepts it to release panel focus, so it never reaches the panel. v cancels instead. +, - and = are likewise reserved by Titah, for panel width.

Known limits

• Untracked files don't appear. git diff doesn't see them, and rendering a whole new file as one giant hunk would push every other change past gitDiffLimit.
• A selection is dropped when the diff itself changes. The panel refreshes at the end of every agent turn, and a selection anchored to lines that have since moved would send a reference to the wrong place — silently, which is worse than losing the selection.
• No syntax highlighting. A panel row carries one colour for the whole line; per-token colour would need spans in the host contract.

Development

npm install
npm run build
npm test

License

Apache-2.0