opencode-tps-meter

A TUI plugin for opencode that displays real-time LLM output speed metrics next to the session prompt.

Display

TPS 42.5 | AVG 38.2 | TTFT 0.8s

• TPS — current tokens per second (live, color-coded)
• AVG — session-wide cumulative average from completed messages (color-coded)
• TTFT — time to first token, shown immediately on first token, persists until next generation (color-coded)

Color Tiers

TPS & AVG (higher is better):

| Tier | Range | Color | |------|-------|-------| | Slow | < 20 TPS | Red | | Normal | 20–50 TPS | Yellow | | Fast | 50–100 TPS | Green | | Faster | > 100 TPS | Cyan |

TTFT (lower is better):

| Tier | Range | Color | |------|-------|-------| | Fast | < 0.5s | Green | | OK | 0.5–2s | Yellow | | Slow | > 2s | Red |

Installation

This plugin must be configured in tui.json (not opencode.json).

Option 1: Local file

1. Copy tui.tsx to your opencode config directory:

cp tui.tsx ~/.config/opencode/tps-meter.tsx

2. Add to ~/.config/opencode/tui.json:

{
  "plugin": [
    "./tps-meter.tsx"
  ]
}

3. Restart opencode.

Option 2: Project-local

Add a .opencode/tui.json in your project root with the same plugin path (relative to the config file location).

How It Works

Live TPS

Tracks text/reasoning delta events in a rolling 5-second window. Uses wall-clock duration (now - oldest sample) instead of inter-arrival time sums to avoid inflation from network buffering.

Token estimation uses ceil(byteLength / 4) with a calibration factor: when a message completes, the estimated token count is compared against actual tokens.output + tokens.reasoning from the message metadata, and a running median ratio corrects future estimates.

AVG

Session-wide cumulative average from all completed messages: sum(actual tokens) / sum(generation durations). Updates only when a message completes. Generation duration = last delta - first delta per message (excludes tool execution time and TTFT).

TTFT

Time from message creation (info.time.created) to the first text/reasoning delta. Displayed immediately when the first token arrives, and persists until the next generation starts.

Development

npm install
npm test

Pure measurement functions (measure.ts) have 29 unit tests. The TUI plugin (tui.tsx) is a standalone single file (all functions inline) for direct deployment — copy it to your config directory.

Requirements

• opencode >= 1.4.3
• The plugin file must be placed where tui.json can reference it via relative path

License

MIT