OpenCode Reminders Plugin

Schedule actions to run at intervals in OpenCode sessions. Set one-time or recurring reminders that execute prompts automatically.

Features

• ⏰ One-time reminders - Execute an action after a delay
• 🔄 Recurring reminders - Execute an action at regular intervals
• 💾 Persistent - Survives OpenCode restarts
• 🧹 Auto-cleanup - Removes reminders when sessions are deleted
• 🔒 Session-scoped - Reminders tied to specific sessions

Installation

bun install opencode-reminders

Then add to your opencode.json:

{
  "plugin": [
    "opencode-reminders"
  ]
}

OpenCode will automatically load the plugin when you start the TUI.

Usage

Set a Reminder

One-time (execute once after delay):

"In 5 minutes, check the build status"

Recurring (execute repeatedly):

"Every hour, check for new emails and summarize them"

List Reminders

"What reminders do I have?"
"Show my active reminders"

Remove a Reminder

"Stop checking my email"
"Cancel the build status reminder"

How It Works

1. Storage - Reminders saved as JSON files in .opencode/reminders/<project-id>/
2. Scheduling - Uses setTimeout to schedule executions
3. Execution - Sends prompt to session when timer fires
4. Cleanup - Removes reminders when session deleted

Multi-Process Semantics

When independent OpenCode server processes load the same reminder directory on one host, an occurrence lease prevents them from submitting the same prompt concurrently. Leases and reminder JSON updates use same-directory atomic filesystem operations. A losing process keeps an unref'd reconciliation timer, reloads durable state, and schedules the winner's next recurring occurrence. Post-prompt recurrence updates and every plugin cancellation/restore cleanup share a short-lived per-reminder mutation lock, so the durable read-and-transition cannot race a deletion. The lock is not held while the prompt API runs.

Reconciliation retries use capped exponential backoff. A recurring occurrence found overdue during startup retains its skip-overdue policy across read or atomic-write failures, so unchanged old JSON is never reinterpreted as a normal occurrence and prompted. Normal runtime failures retain the occurrence for an at-least-once retry; the retry history resets after durable state advances into the future.

Within one server process, plugin generations also fence hot reloads. Reinitialization clears old timers, aborts active requests, waits for mutations already in progress, and prevents stale timer or reconciliation callbacks from changing replacement state. Cancellation aborts the active local request immediately, then uses the same mutation lock as cross-process transitions.

Reconciliation reads are fenced per reminder and revalidated under the mutation lock. Once local cancellation returns, a read that completed before deletion cannot restore stale list state or a timer, even if its continuation resumes later.

If durable cancellation fails, the plugin re-reads authoritative state through the same fence and lock protocol, restores a delayed timer, and returns the original deletion error. The reminder stays visible and can be cancelled again without restarting the server.

This is deliberately not a claim of crash-proof exactly-once delivery. Any process, storage, or lock failure after the prompt API accepts a request but before its durable transition can lead to retry. That is at-least-once crash semantics; true exactly-once delivery requires idempotency support in the prompt API. Likewise, cancellation does not hold a lock across prompting: if an owner has already passed durable validation, a prompt can still be submitted even when cancellation returns first. The post-prompt durable transition remains fenced, so cancellation cannot intentionally resurrect or reschedule the reminder after deletion.

The lease protocol assumes same-host processes and a local filesystem with atomic hard links, exclusive create, and rename. It is not intended to coordinate hosts or provide NFS/distributed filesystem safety. Linux detects a dead or reused PID using /proc/<pid>/stat process start time. Other platforms may acquire leases normally, but only reclaim a lease when process.kill(pid, 0) reports ESRCH; a reused PID is conservatively treated as live and can leave a stale lease until manual cleanup rather than risk a duplicate prompt.

A stale .recover guard is never reclaimed automatically. This avoids a replacement race that could delete a live guard or lease, at the cost of manual cleanup after a recovery-process crash.

Reminders capture the creating tool context's optional agent name and pass it back to the prompt API when they execute. Existing reminder files without agent remain valid and omit the prompt field.

Data Storage

Reminders stored in:

.opencode/
  reminders/
    <project-id>/
      <reminder-id>.json
    .gitignore

The .gitignore file is automatically created to exclude reminder data from version control.

Configuration

The plugin supports the following configuration options (set via plugin config):

{
  reminders: {
    enabled: true,                    // Enable/disable plugin
    max_reminders_per_project: 50,    // Maximum reminders per project
    min_interval_seconds: 30,         // Minimum interval between executions
    notifications: {
      enabled: true                   // Enable/disable toast notifications
    }
  }
}

Development

Install Dependencies

bun install

Type Check

tsc --noEmit

Run Tests

# Run all tests
bun test

# Run specific test suites
bun test test/types.test.ts
bun test test/storage.test.ts
bun test test/logger.test.ts
bun test test/config.test.ts
bun test test/scheduler.test.ts
bun test test/integration.test.ts

# Watch mode
bun test --watch

# Using npm scripts
npm run test
npm run test:types
npm run test:storage
npm run test:logger
npm run test:integration
npm run test:watch

Test Coverage: Comprehensive test suite covering types, storage, logging, configuration, scheduling, and integration.

Architecture

This plugin demonstrates a multi-file structure:

• index.ts - Main plugin export with tool definitions and event handlers
• types.ts - TypeScript types and Zod schemas
• storage.ts - Filesystem operations for persistence
• scheduler.ts - Timer management and execution logic
• logger.ts - Logging functionality with configurable levels
• tools/ - Tool implementations (reminderadd, reminderlist, reminderremove)
• test/ - Comprehensive test suite
• package.json - Dependencies configuration
• tsconfig.json - TypeScript configuration

Troubleshooting

Reminders not executing?

• Check session still exists
• Verify reminder shows in list
• Check console for errors

Reminders lost after restart?

• Ensure storage directory not deleted
• Check file permissions

Too many reminders?

• Default limit: 50 per session
• Remove old reminders before adding new ones

License

MIT