I was following Pi agent development, and intrigued by oh-my-pi, but decided to start building on top of opencode instead.
I am starting to regret that decision, but will see how far it goes.

Vibe-kit Disclaimer

I absolutely loved this blog post https://blog.can.ac/2026/02/12/the-harness-problem/ because I see failed edits constantly with Local LLMs, and this is a novel approach.
Is it very novel though? BASIC had lines that start with indexes, too. I want to use it, anyway. GOTO 200.

200 I am attempting to create a CLI version of this edit tool for later opencode integration, but it might stand alone. This was initially ported from oh-my-pi with LLM help into an opencode tool, then later extracted as a Rust CLI.

Usage in OpenCode

Run cargo install --path . or create a wrapper script called 'hashline-tools' over cargo run.

Copy the typescript wrappers in ./opencode-tools to ~/.config/opencode/tools or a specific project folder's .opencode.

Hash-Aware Diff Format

After applying edits, the tool returns a custom diff format that includes freshly calculated hashes for immediate reuse:

Edit applied successfully (first change at line 8).

<diff>
--- /tmp/file.txt
+++ /tmp/file.txt
 3#NQ:line 3
 4#RH:line 4
 5#XH:line 5
 6#ZT:line 6
 7#BX:line 7
-8#  :line 8
+8#RT:modified line 8
 9#PJ:line 9
 10#NV:line 10

Note: Lines after edited regions have stale hashes. Use hashread to refresh.
</diff>

Format:

• LINE#HASH:content for context and inserted lines (fresh hashes)
• LINE# :content for deleted lines (no hash, shown as 2 spaces)
• ±5 lines of context around each change
• Shows ... for gaps between change regions
• Terse note: "Lines after edited regions have stale hashes. Use hashread to refresh."

This allows successive edits without an intermediate hashread call - just copy the LINE#HASH anchor from the diff output.

API Format Changes from Original

This implementation diverges from oh-my-pi in several ways:

Anchor Format

Original: {line: 8, hash: "RT"} (object)

This implementation: "8#RT" (string)

The string format aligns with:

• hashread output: 8#RT:line content
• hashedit input: "pos": "8#RT"
• diff output: +8#RT:modified content

Edit Operations

Replace single line:

{
  "op": "replace",
  "pos": "8#RT",
  "lines": ["new content"]
}

Replace range:

{
  "op": "replace",
  "pos": "6#ZT",
  "end": "10#NV",
  "lines": ["replaced content"]
}

Append after line:

{
  "op": "append",
  "pos": "8#RT",
  "lines": ["new line after"]
}

Append to EOF:

{
  "op": "append",
  "lines": ["new line at end"]
}

Prepend before line:

{
  "op": "prepend",
  "pos": "8#RT",
  "lines": ["new line before"]
}

Prepend to BOF:

{
  "op": "prepend",
  "lines": ["new line at start"]
}

Delete single line:

{
  "op": "delete",
  "pos": "8#RT"
}

Delete range:

{
  "op": "delete",
  "pos": "6#ZT",
  "end": "10#NV"
}

Known Issues

• Diffs are not easily displayed in the opencode TUI due to external tool restrictions anomalyco/opencode#6831 (comment)