creating-opencode-plugins

A guide for building OpenCode plugins, which are JavaScript or TypeScript modules that react to events in the OpenCode coding assistant. They can observe or extend actions involving files, commands, permissions, sessions, tools, and the user interface.

In plain words
What is it for?
Use it to create plugins that monitor commands, protect sensitive files, process language-server diagnostics, manage permissions, register tools, or respond to session and interface events.
Why use it?
It provides the structure and event API needed to connect custom behavior to the assistant's lifecycle. This avoids using a plugin for tasks better handled by prompts, scripts, or configuration.

Skill for Claude CodeCodex

Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

agentmods
npx agentmods add skills/pr-pm/prpm/creating-opencode-plugins
Any agent
npx skills add pr-pm/prpm --skill creating-opencode-plugins
Clone the repo
git clone --depth 1 https://github.com/pr-pm/prpm

Made for: Claude Code, Codex.

Per session 59 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 2,478 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
Origin original No closer match found in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5 $0.00059 $0.02478
Opus 5 $0.00030 $0.01239
Sonnet 5 $0.00012 $0.00496
Haiku 4.5 $0.00006 $0.00248

Measured 2d ago against content hash 9c19f8fc9832, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

creating-opencode-plugins scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 2d ago.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

.claude/skills/creating-opencode-plugins/SKILL.md · 386 lines

How it starts

The opening of the file, as written. The whole thing — 386 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Creating OpenCode Plugins

Overview

OpenCode plugins are JavaScript/TypeScript modules that hook into 25+ events across the OpenCode AI assistant lifecycle. Plugins export an async function receiving context (project, client, $, directory, worktree) and return an event handler.

When to Use

Create an OpenCode plugin when:

  • Intercepting file operations (prevent sharing .env files)
  • Monitoring command execution (notifications, logging)
  • Processing LSP diagnostics (custom error handling)
  • Managing permissions (auto-approve trusted operations)
  • Reacting to session lifecycle (cleanup, initialization)
  • Extending tool capabilities (custom tool registration)
  • Enhancing TUI interactions (custom prompts, toasts)

Don't create for:

  • Simple prompt instructions (use agents instead)
  • One-time scripts (use bash tools)
  • Static configuration (use settings files)

Quick Reference

Plugin Structure

export const MyPlugin = async (context) => {
  // context: { project, client, $, directory, worktree }

  return {
    event: async ({ event }) => {
      // event: { type: 'event.name', data: {...} }

      switch(event.type) {
        case 'file.edited':
          // Handle file edits
          break;
        case 'tool.execute.before':
          // Pre-process tool execution
          break;
      }
    }
  };
};

Event Categories

Category Events Use Cases
command command.executed Track command history, notifications
file file.edited, file.watcher.updated File validation, auto-formatting
installation installation.updated Dependency tracking
lsp lsp.client.diagnostics, lsp.updated Custom error handling
message message.*.updated/removed Message filtering, logging
permission permission.replied/updated Permission policies
server server.connected Connection monitoring
session session.created/deleted/error/idle/status/updated/compacted/diff Session management
todo todo.updated Todo synchronization
tool tool.execute.before/after Tool interception, augmentation
tui tui.prompt.append, tui.command.execute, tui.toast.show UI customization

Read the full file on GitHub · 386 lines

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. 2d ago First seen · 386 lines · 59 tokens per session scan A 9c19f8fc9832

Subscribe to this mod's changes

creating-opencode-plugins is a skill published in the GitHub repository pr-pm/prpm (120 stars, last pushed 2mo ago), licensed MIT. It adds 59 tokens to every session and 2,478 once invoked, about $0.0003 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.