opencode-costs

Show LLM costs and token usage per agent in OpenCode sidebar.

Why

OpenCode shows total token usage per session, which works fine when you have a single agent. But once you start working with multiple agents — a planner that delegates to a backend-dev, a frontend-dev, a reviewer, and a scriber — you lose visibility into who's spending what.

This plugin breaks down costs per agent, so you can see at a glance which agents are the most expensive, where token usage piles up, and whether your delegation strategy is cost-effective.

What it looks like

Costs  $0.615764  549.6K tok
qa  $0.137073  53.2K tok  (1)
scriber  $0.110440  55.1K tok  (1)
backend-dev  $0.104367  53.2K tok  (1)
frontend-dev  $0.090654  43.3K tok  (1)
plan  $0.082858  235.6K tok  (1)
system-analyst  $0.079053  38.6K tok  (1)
consult  $0.011319  70.7K tok  (1)

Install

1. Open OpenCode
2. Press Ctrl+P (or Cmd+P on macOS)
3. Select Install Plugins
4. Type opencode-costs and hit Enter

Done. Costs will appear in the sidebar on your next session.

Configuration

Override the refresh interval via environment variable:

OPENCODE_COSTS_REFRESH_MS=30000 opencode

| Option | Default | Description | |--------|---------|-------------| | OPENCODE_COSTS_REFRESH_MS | 15000 | Sidebar refresh interval in milliseconds (min 1000) |

How it works

Reads session history via OpenCode API, groups by agent (e.g. plan, build, default), shows cumulative cost ($) and token usage in the sidebar. Refreshes automatically and on session events.

Known Limitations

• Agent attribution when switching with Tab: OpenCode reuses the same session when switching between Plan/Build agents, so all costs are attributed to the last active agent. This is an API limitation, not a plugin bug. Totals ($, tok) remain correct.
• Current directory only: Only sessions from the current project directory are shown.
• TUI only: This plugin only works in TUI mode, not CLI.

License

MIT