Hashline

OpenCode plugin adapter for hashline — compact, line-anchored, tag-verified file edits. Powered by @oh-my-pi/hashline.

Instead of exact-string matching (which forces models to re-type old content and risks drift), hashline uses line-number anchors combined with content-hash tags so every edit is validated against the exact file snapshot the model saw. This plugin wraps the hashline engine as an OpenCode edit tool override and snapshot injection hook.

Package name: Published as @debugtalk/opencode-hashline on npm. The unscoped name opencode-hashline is used by a different package on the public registry.

Installation

opencode plugin @debugtalk/opencode-hashline

Install globally:

opencode plugin @debugtalk/opencode-hashline --global

Restart OpenCode. No build step — OpenCode loads the TypeScript plugin entry directly.

Upgrade

opencode plugin @debugtalk/opencode-hashline --force

Verify

grep "opencode-hashline" ~/.local/share/opencode/log/opencode.log

opencode-hashline plugin loaded → success.

How It Works

The plugin overrides the built-in edit tool and injects snapshot tags into read output:

1. Read — output starts with [path/file.ts#A1B2] (4-hex content hash of the file)
2. Edit — [path/file.ts#A1B2] plus line-anchored ops; tag must match current file content
3. Drift — mismatch rejects the edit (with recovery when possible); re-read and retry

Edit syntax (format v2)

[src/foo.ts#A1B2]
SWAP 2.=2:
+    return newValue

INS.POST 10:
+    // new comment

DEL 5.=7

INS.HEAD:
+# SPDX-License-Identifier: MIT

Operation	Syntax	Description
Replace lines	SWAP N.=M:	Replace inclusive range N..M with + body rows
Delete lines	DEL N.=M or DEL N	Delete range; no body
Insert before	INS.PRE N:	Insert before line N
Insert after	INS.POST N:	Insert after line N
Insert head	INS.HEAD:	Insert at file start
Insert tail	INS.TAIL:	Insert at file end
Delete file	REM	Remove entire file (section header required)
Move/rename	MV dest/path	Move file to dest/path

Body rows are +TEXT only. The range deletes; the body is the final content for that range.

Rules

• Line numbers refer to the original file; they do not shift as hunks apply in one patch
• Every successful edit returns a new #TAG — use it for the next edit or re-read
• Ranges should cover only lines that change
• On stale tag or unexpected result: stop and re-read

Configuration

No configuration required.

Programmatic use (hashline core)

Use the upstream package directly:

import { Patch, Patcher, NodeFilesystem, InMemorySnapshotStore } from "@oh-my-pi/hashline";

Limitations

• SWAP.BLK N: not supported — tree-sitter block resolver not bundled; use SWAP N.=M: line ranges
• OpenCode only — this npm package targets the OpenCode plugin runtime; see docs/cross-platform-plugins.md for other agents

Docs

• Test design
• Comparison vs built-in edit

License

MIT