opencode-special-edition

MOSTLY CLANKER-BUILT

OpenCode plugin that shortens the default system prompt and built-in tool descriptions so each request sends fewer tokens. Inspired by the minimal style of pi.

The built-in JSON parameter schemas for tools are unchanged. This package only replaces the long prose descriptions where a shorter version exists.

What it does

System prompt

Replaces OpenCode’s default system prompt with a shorter version from prompt/default.txt. Keeps the environment block (model name, cwd, date), the skills block (see below), and AGENTS.md content when OpenCode composes the default layout.

Skills section (not modified by this plugin)

OpenCode adds a separate system fragment listing discovered skills (from SKILL.md files under paths such as skill/, skills/, .claude, .agents). It is built in SystemPrompt.skills and concatenated with env + instructions when assembling the prompt. Typical shape:

Skills provide specialized instructions and workflows for specific tasks.
Use the skill tool to load a skill when a task matches its description.
<available_skills>
  <skill>
    <name>…</name>
    <description>…</description>
    <location>file://…</location>
  </skill>
  …
</available_skills>

If no skills are loaded, the third part is the line No skills are currently available. If the agent has the skill permission disabled, this block is omitted entirely.

Tool descriptions

Supplies shorter description strings from tool/<tool-id>.txt for built-in tools OpenCode exposes. Parameter schemas are still the full definitions from OpenCode.

Rough size comparison

| Component | Typical before | With this plugin | Approx. savings | |-----------|----------------|------------------|-----------------| | System prompt (provider text only) | ~1800 tokens | ~100 tokens | ~1700 | | Tool descriptions | ~5500 tokens | ~350 tokens | ~5150 | | Skills section | (unchanged) | (unchanged) | — | | Total (order of magnitude) | | | ~6850 |

Exact counts depend on model tokenizer and OpenCode version.

Install

From npm

npm install @anthonyfangqing/opencode-special-edition

In opencode.json / opencode.jsonc:

{
  "plugin": ["@anthonyfangqing/opencode-special-edition"]
}

Local path

{
  "plugin": ["./path/to/opencode-special-edition/index.ts"]
}

Project plugin directory

Copy or link the package under .opencode/plugins/ (see OpenCode plugins). Files there load automatically; you do not have to list them in plugin unless you also use npm plugins and want a specific setup.

Customization

• Project rules: use AGENTS.md; this plugin keeps that content when it is injected into the default prompt shape.
• Full custom system prompt: set agent.build.prompt in config. The plugin skips rewriting when the prompt does not look like the default.

What it does not change

• The skills fragment OpenCode adds (Skills provide specialized…, <available_skills>, etc.): this plugin does not remove or edit it; it remains after the env block in the composed system text.
• JSON parameter schemas for tools (still full definitions)
• Environment lines (model, cwd, date) when present in the default prompt
• AGENTS.md text when present in the composed prompt
• Plan-mode reminders, compaction/summary/title prompts, or other internal agent prompts
• MCP tool descriptions (only OpenCode’s built-in tools are overridden here)

Publish

From this directory, logged in as a member of the anthonyfangqing org (npm login):

npm publish

package.json sets publishConfig.access to public so the scoped package is visible without passing --access public. Use npm pack --dry-run to inspect the tarball before publishing.