Throughput

Real-time LLM performance monitoring plugin for OpenCode. Tracks latency, throughput, token usage, and cost per model with toast notifications and JSONL logging.

Features

• TTFT (Time To First Token) — measures how fast the model starts generating
• TPS (Tokens Per Second) — generation throughput during streaming
• Total Latency — end-to-end request time
• Token Usage — input, output, reasoning, cache read/write
• Cost Tracking — per-request and cumulative cost
• Toast Notifications — real-time performance summary after each LLM response
• JSONL Logging — persistent logs at ~/.opencode/throughput.jsonl
• Benchmark Tool — query historical stats on demand from the AI agent

Installation

Add to your opencode.json:

{
  "$schema": "https://opencode.ai/config.json",
  "plugin": ["opencode-throughput"]
}

OpenCode will automatically install the plugin from npm at startup.

Usage

Once installed, the plugin runs automatically:

1. After each LLM response, a toast notification appears with metrics:

   claude-sonnet-4 | 2.1s TTFT | 58.3 tok/s | 4.2s | ↑1.2k ↓892
   

2. Logs are written to ~/.opencode/throughput.jsonl (one JSON object per line)

3. Query benchmarks — ask the AI agent to use the benchmark tool:

   "Show me the benchmark stats for claude" "Compare model performance" "Show the last 10 requests"

Benchmark Tool Args

Arg	Type	Description
model	string (optional)	Filter by model name (partial match)
last	number (optional)	Only show the last N entries

Log Format

Each line in ~/.opencode/throughput.jsonl:

{
  "ts": "2026-03-21T10:00:00.000Z",
  "model": "anthropic/claude-sonnet-4",
  "providerID": "anthropic",
  "modelID": "claude-sonnet-4",
  "sessionID": "abc123",
  "messageID": "def456",
  "ttft_ms": 2100,
  "tps": 58.3,
  "latency_ms": 4200,
  "inputTokens": 1200,
  "outputTokens": 892,
  "reasoningTokens": 0,
  "cacheReadTokens": 500,
  "cacheWriteTokens": 200,
  "cost": 0.0234,
  "finish": "stop"
}

How It Works

The plugin hooks into OpenCode's event system:

• message.updated — captures AssistantMessage.time.completed, tokens, and cost
• message.part.updated — captures the first TextPart.time.start for TTFT calculation

Development

Local development

{
  "plugin": ["file:///absolute/path/to/opencode-throughput/src/index.ts"]
}

Build

bun install
bun run build

Publish

npm publish --access public

License

MIT