opencode-context-limit

An OpenCode V2 plugin that sets a working context budget per model. Lower it to make compaction fire earlier than the catalog window, for cost tiers or when a provider serves less than the catalog claims. The budget never raises the window.

OpenCode

This plugin runs on OpenCode. New accounts through my referral link get $5 in usage credits, and I get $5 too:

https://opencode.ai/go?ref=N9H3ZEP22A

Install

mkdir -p ~/.config/opencode/plugins
curl -fsSL \
  https://raw.githubusercontent.com/jadmadi/opencode-context-limit/main/context-limit.ts \
  -o ~/.config/opencode/plugins/context-limit.ts

For one project, put it in .opencode/plugins/. Tested against OpenCode v2.0.3.

To pin a release, replace main in the URL with a tag such as v0.1.0.

Use

Command	Effect
/context-limit	Show the budget for the current model
/context-limit 128K	Set it for the current model
/context-limit 50%	Set half the catalog window
/context-limit opencode-go/* 128K	Set a pattern
/context-limit <target> 0	Clear a target

Values accept plain tokens (128000), 128K, 1M, and 50%. Every value is clamped to the catalog window, so it can only lower the budget, never raise it.

Patterns match provider/model. opencode-go/* matches one provider, * matches everything. The longest matching pattern wins.

How it works

The plugin registers a catalog transform that lowers the matched models' limit.context. Compaction's default threshold follows the model's usable input budget, so compaction fires earlier. A change calls ctx.catalog.reload() and applies at once. Nothing is written to opencode.json.

Tests

bun test

Attribution

Inspired by MiMoCode's /context-limit. See NOTICE.

License

MIT