hashline-opencode

OpenCode plugin that replaces the built-in edit tool with hash-anchored LINE#ID precision editing.

What is LINE#ID?

LINE#ID is a content-addressed line reference format. Each line gets tagged with a hash derived from its content.

{line_number}#{hash_id}|content

• hash_id: Two characters from the CID set ZPMQVRWSNKTXJBYH
• Computed using xxHash32 via Bun's built-in Bun.hash.xxHash32
• Example: 42#VK means line 42 with hash VK

This prevents editing the wrong line. If a file changes after you read it, the hash won't match and the edit is rejected before any corruption happens.

Installation

Option 1: npm

npm install hashline-opencode

Then add to your opencode.json:

{
  "plugins": ["hashline-opencode"]
}

Option 2: Local plugin directory

Place the plugin in .opencode/plugins/hashline-opencode/ and reference it:

{
  "plugins": ["./.opencode/plugins/hashline-opencode"]
}

Option 3: Global plugin (symlink)

Symlink the built dist/index.js directly into the global plugin directory:

mkdir -p ~/.config/opencode/plugins
ln -s /path/to/hashline-opencode/dist/index.js ~/.config/opencode/plugins/hashline-opencode.js

The file must live directly in ~/.config/opencode/plugins/ — symlinks to directories won't work.

What it does

• Replaces built-in edit tool with hashline_edit using LINE#ID hash anchors
• Hooks into tool.execute.after to add LINE#IDs to all read tool output
• Annotates @-mentioned files with LINE#IDs — unlike other implementations, this plugin intercepts OpenCode's experimental.chat.messages.transform hook to process files included via @filename, so the AI receives correct hashes immediately without a separate read step
• Validates hashes before applying edits — rejects stale references
• Supports three operations: replace, append, prepend
• Applies edits bottom-up to preserve line numbers during multi-edit
• Auto-corrects: restores indentation, preserves BOM/CRLF, expands merged lines

LINE#ID Format

When the plugin is active, read output looks like this:

1#XN|import type { Plugin } from "@opencode-ai/plugin"
2#WW|import { createHashlineEditTool } from "./tools/hashline-edit"
3#TY|import { createHashlineReadEnhancerHook } from "./hooks/hashline-read-enhancer"

To edit line 2, reference its full LINE#ID:

{
  "filePath": "src/index.ts",
  "edits": [
    {
      "op": "replace",
      "pos": "2#WW",
      "lines": "import { createHashlineEditTool, applyHashlineEdits } from \"./tools/hashline-edit\""
    }
  ]
}

Rules:

• Use {line_number}#{hash_id} only — never include the |content part
• Copy tags exactly from read output
• Always anchor to structural lines (functions, classes, braces), never blank lines
• Batch all edits for one file in a single call
• Re-read the file before making another edit call

Requirements

• Bun runtime (uses Bun.hash.xxHash32)

License

SUL-1.0