opencode-plugin-snip

opencode-plugin-snip is an OpenCode plugin that reduces prompt size before messages are sent to the LLM, then shows the saved-character total live in the TUI.

It is built around one constraint: compression must be deterministic. The same input history should compress the same way every time, so you get smaller prompts without introducing cache-hostile randomness or paying for an extra model pass.

Why this plugin stands out

• Deterministic compression. No LLM rewriting step, no probabilistic summarization, no drifting history.
• Zero extra model cost. Compression is done with fixed rules over message parts and text.
• Session-scoped savings. Every session tracks its own saved-character total and starts from 0.0k.
• Live TUI feedback. The current mode and cumulative savings are visible in the prompt row.
• Tool-aware cleanup. Tool payloads are normalized instead of blindly dumped back into history.
• Protected-block safe. <system-reminder>...</system-reminder> blocks are preserved.
• Three compression levels. Choose pro, max, or max++ depending on how aggressive you want to be.

Features

• Removes framework control events such as [step-start], [step-finish], and [reasoning] when they appear in framework-event form.
• Preserves non-framework user text that merely contains similar markers.
• Preserves <system-reminder>...</system-reminder> blocks.
• Normalizes tool output in max and max++ modes.
• Truncates oversized tool output in max++ mode.
• Tracks saved characters per session, not globally.
• Adds a bright yellow snip label to home_prompt_right and session_prompt_right.
• Keeps optional request logging off by default.

What you see

In the TUI, the plugin shows a label like this:

snip max 12.4k

Meaning:

• snip is the plugin label.
• max is the active compression mode.
• 12.4k is the cumulative characters saved for the current session only.

Install

Install from npm through OpenCode:

opencode plugin opencode-plugin-snip

If you want to install to the global OpenCode config scope, use:

opencode plugin opencode-plugin-snip --global

OpenCode detects the plugin package from these exports:

• exports["./server"]
• exports["./tui"]

After install, OpenCode patches the relevant config files for you.

Configuration

After install, OpenCode writes plugin entries into opencode.json and tui.json.

The server plugin supports these options:

{
  "mode": "max",
  "logEnabled": false,
  "logPath": "C:/path/to/opencode-llm.log",
  "toolMaxLines": 40,
  "toolMaxChars": 4000
}

logEnabled defaults to false.

Modes

pro

• Smallest behavior change.
• Best when you want conservative cleanup.
• Keeps tool payloads mostly intact.

max

• Default mode.
• Removes framework noise.
• Normalizes tool payloads.
• Best general-purpose setting.

max++

• Same as max, plus truncates tool output using toolMaxLines and toolMaxChars.
• Best when tool output is the main source of prompt bloat.

TUI behavior

• The mode label comes from the server plugin config.
• The number is the cumulative saved characters for the current session only.
• A brand-new session starts at 0.0k.
• The home screen shows 0.0k because savings are session-based.

Files written by the plugin

The plugin writes per-user runtime data under the OpenCode config directory:

• ~/.config/opencode/snip-stats.json

Optional log output defaults to:

• ~/opencode-llm.log

How it works

Server side:

• Hooks experimental.chat.system.transform
• Hooks experimental.chat.messages.transform
• Compresses message parts deterministically.
• Removes control-event parts and matching framework-event text lines.
• Rewrites tool payloads into a smaller, stable format.
• Updates per-session saved-character stats.

TUI side:

• Registers home_prompt_right.
• Registers session_prompt_right.
• Polls the stats file and renders live saved-character counts.

Local development

You can also use this package source directly as a local plugin during development.

Replace /absolute/path/to/opencode-plugin-snip with your own local checkout path.

Example opencode.json:

{
  "plugin": [
    [
      "/absolute/path/to/opencode-plugin-snip/src/server.js",
      {
        "mode": "max",
        "logEnabled": false,
        "toolMaxLines": 40,
        "toolMaxChars": 4000
      }
    ]
  ]
}

Example tui.json:

{
  "$schema": "https://opencode.ai/tui.json",
  "plugin": [
    "/absolute/path/to/opencode-plugin-snip/src/tui.tsx"
  ]
}

Publish to GitHub

This directory is ready to become a GitHub repository.

Typical steps:

git init
git add .
git commit -m "Initial plugin package"
gh repo create opencode-plugin-snip --public --source . --remote origin --push

Publish to npm

After the GitHub repo is ready and the package name is available:

npm publish --access public

If the package name is already taken, rename the name field in package.json first.

Notes

• Do not publish your personal opencode.json with provider credentials.
• This package only contains the plugin code and documentation.
• The stats file is intentionally session-scoped so session totals do not bleed into each other.