SoL-OpenCode

SoL-OpenCode brings SoL-Pi's four token-efficiency mechanisms to OpenCode v2 as a plugin built on @opencode/plugin. It is a port of SoL-Pi, which NVIDIA released under the MIT license for the Pi coding agent. SoL-OpenCode is not an NVIDIA or OpenCode project.

Spend less without making the agent do less useful work. Each mechanism is opt-in and disabled by default.

Area	Mechanism	What changes
Tools	Action Fusion	edit and write accept an optional then_run command that runs in the same tool call, through OpenCode's own shell tool.
Observations	ObservationPack	Large tool results are sent in full twice, then replaced in outgoing requests by a stable placeholder, with exact paged recall through obs_recall.
Delegation	Evidence-Preserving Reducer	Long diagnostic logs become compact receipts through a reducer model, accepted only when every quote matches the archived source byte for byte.
Context	Online Context Compact	Completed plan steps (update_plan) become candidate compaction points, subject to an economic check (cacheWriteReadRatio) and window pressure.

The rules carry over from SoL-Pi:

• No OpenCode patches. Only the public @opencode/plugin API is used.
• Explicit opt-in. A missing configuration leaves every mechanism disabled.
• Preserve evidence. Originals stay archived locally, and any mechanism failure leaves the original result or request unchanged.
• Persisted history is never edited. ObservationPack and Online Context Compact change only the outgoing request.
• Use OpenCode's runtime choices. Authentication, providers, the main model, and the shell stay under OpenCode's control. The reducer and the compaction summary go through ctx.generate.text and ctx.session.generate.

Online Context Compact works differently from SoL-Pi. OpenCode v2.0.18 gives plugins no way to request its own compaction, so a selected plan boundary is compacted in the outgoing request: the older messages are summarized once (reusing the cached prefix), and later requests carry the summary in their place. See docs/compatibility.md for this and the other differences.

Requirements

• OpenCode 2.0.18 (npm install -g @opencode/cli@2.0.18)
• Node.js 22.19 or newer and npm, to install this package's dependencies

Install

Clone the repository and install its locked dependencies:

git clone https://github.com/balcsida/SoL-OpenCode
cd SoL-OpenCode
npm ci --ignore-scripts

Then load it in one of two ways.

Option 1: a plugins entry, with the configuration as options. In opencode.jsonc (project or ~/.config/opencode/):

{
  "$schema": "https://opencode.ai/config.json",
  "plugins": [
    {
      "package": "/absolute/path/to/SoL-OpenCode",
      "options": { "version": 1, "actionFusion": true, "observationPack": true }
    }
  ]
}

Option 2: auto-discovery, with sol-pi.json. Create .opencode/plugins/sol-opencode.ts in a project (or ~/.config/opencode/plugins/ for every project) containing:

export { default } from "/absolute/path/to/SoL-OpenCode/src/index.ts";

Then put the configuration in .opencode/sol-pi.json or ~/.config/opencode/sol-pi.json.

Configure

This conservative configuration enables only the two mechanisms that make no extra model calls:

{
  "version": 1,
  "actionFusion": true,
  "observationPack": true,
  "evidencePreservingReducer": false,
  "onlineContextCompact": false,
  "cacheWriteReadRatio": 12.5
}

Plugin options, when present, replace the files; the project file replaces the global one. Sources are never merged. sol-pi.example.json lists every key, and docs/configuration.md has the schema, defaults, and search order.

The reducer defaults to openai/gpt-5.6-luna through OpenCode's model runtime. Set evidencePreservingReducerProvider and evidencePreservingReducerModel to route it elsewhere. Credentials stay in OpenCode.

Storage and security

• Archives: ObservationPack and the reducer archive originals under <OpenCode data>/sol-opencode/<sessionID>/, normally ~/.local/share/opencode/sol-opencode/. The archives stay local and are not deleted automatically.
• State: Online Context Compact keeps its per-session state in OpenCode's plugin storage.
• Remote reduction: the reducer may send eligible diagnostic logs to its configured model.

Read SECURITY.md before enabling the reducer.

Documentation

Document	Purpose
docs/configuration.md	Sources, schema, defaults, runtime inputs
docs/compatibility.md	OpenCode APIs used, host behaviour relied on, differences from SoL-Pi
docs/verification.md	Live results on OpenCode 2.0.18
docs/port-audit.md	The Pi → OpenCode v2 API audit behind the port
SECURITY.md	Local storage, remote reduction, sensitive behavior

Development

npm ci --ignore-scripts
npm run check                     # tsc + the zero-spend test suite
scripts/live/verify.sh af-op      # real OpenCode session, Action Fusion + ObservationPack
scripts/live/verify.sh all        # real OpenCode session, all four mechanisms

The live checks need opencode 2.0.18 on PATH. They use a scripted local endpoint, so they need no credentials and cost nothing. ./upstream/ is an optional, git-ignored clone of SoL-Pi kept for reference.

License

MIT. SoL-OpenCode derives from SoL-Pi (Copyright © 2026 NVIDIA Corporation & Affiliates, MIT); see LICENSE and THIRD_PARTY_NOTICES.md. The research behind the mechanisms is described in the SoL-Pi paper and blog.