opencode-dcp

Dynamic Context Pruning (DCP) for OpenCode V2.

Keeps the model's context window high-signal by letting the model compress closed sections of the conversation into its own dense technical summaries, pruning superseded tool outputs, and nudging when context pressure crosses a budget.

Requires OpenCode V2 (opencode2). The plugin API is beta; pin versions that match your OpenCode release.

Install

opencode2 plugin add opencode-dcp

This installs the package into OpenCode's plugin cache and registers its server entrypoint in your global config. The TUI companion needs no extra step: the plugin's definition sets tui: true, so a locally connected TUI discovers the active plugin and loads its ./tui export from the cache on its own. Or add it directly to a project config:

{
  "plugins": [
    {
      "package": "opencode-dcp",
      "options": {
        "debug": false,
        "maxContextLimit": "70%"
      }
    }
  ]
}

Development (this repo): build first (npm install && npm run build), then point config at the local entrypoint:

{
  "plugins": [
    {
      "package": "../dist/index.js",
      "options": {
        "debug": true,
        "maxContextLimit": "70%",
        "tui": { "enabled": false }
      }
    }
  ]
}

Note: the automatic TUI companion load only applies to packages installed via plugin add. With a local-path entry like above, the sidebar/report stay off unless you separately register the TUI module (e.g. a cli.json plugins entry or a file under ~/.config/opencode/plugins/tui/).

Requires OpenCode V2 (opencode2). OpenCode V2 auto-updates, so the package tracks @opencode-ai/plugin@beta (the dist-tag resolves to the latest tagged beta at install time; the committed lockfile pins the exact resolved version for local dev). Don't use a caret range (^0.0.0-beta-…) — npm treats any lexically-greater 0.0.0-* prerelease as satisfying the range, and junk tags like windows-fix lack the Plugin export.

How it works

On every model dispatch (ctx.session.hook("context")) the plugin transforms the outbound transcript only — stored session history is never modified:

1. Scan & mirror — index the transcript with stable keys; remember it so the prune tool can resolve ranges.
2. Boundary IDs — every message gets an alias m0001, m0002, … injected as <dcp-message-id> tags on user texts and textual tool results. Compressed sections are addressed as b1, b2, ….
3. Compression blocks — active blocks remove their covered ranges and splice a synthetic [Compressed conversation section] summary at the recorded anchor.
4. Pruning — superseded/errored tool outputs are replaced with short placeholders (protected tools like question/edit are never touched).
5. Nudges — when provider usage crosses maxContextLimit, a reminder asks the model to run prune; rate-limited by nudgeFrequency.

The model calls prune itself (registered with the platform default codemode: true, so it is exposed through the Code Mode tools.prune catalog in agentic sessions; named prune to avoid clashing with the platform's built-in compress tool). It picks non-overlapping ranges by boundary ID and writes dense summaries per range. A range may cover previously pruned blocks: including (bN) carries that block's full content forward, omitting it permanently drops the block's content from context — how stale completed work gets pruned. Deduplication and error-purge strategies run at compression time so idle sessions keep their prompt-cache prefix stable. State persists per session across restarts via plugin storage.

TUI panel

A companion TUI module ships with the package and is enabled by default (the server definition sets tui: true). While a session runs it shows:

• Sidebar footer: live outbound-token savings of the last dispatch (−38% · 21.3k→13.2k tok) plus active block count.
• Command palette → "DCP: compression report": per-session totals (dispatches, compressions, blocks), last-dispatch delta, cumulative token savings from blocks and pruning, and the most recent compression events.

Mechanism: the server plugin writes a stats snapshot to the TUI's watched storage file (~/.local/state/opencode/<channel>/tui/plugin.opencode.dcp.tui.stats.json) after every dispatch and compression; the TUI module reads it as a reactive store, so numbers update live. Disabling stops stats writes and quiets the panel:

{
  "plugins": [
    {
      "package": "opencode-dcp",
      "options": { "tui": { "enabled": false } }
    }
  ]
}

Commands

| Command | Effect | | ------- | ------ | | /dcp-prune [focus] | Instructs the model to run a pruning pass now |

Options

All optional (defaults shown):

{
  "enabled": true,
  "debug": false,
  "allowSubAgents": false,          // run inside sub-agent sessions
  "maxContextLimit": 70000,         // absolute tokens, or "NN%" of the model window
  "nudgeFrequency": 5,              // min messages between nudges
  "iterationNudgeThreshold": 0,     // messages since last user turn before an iteration nudge (0 = off)
  "protectedTools": [],             // globs never auto-pruned ("mcp*")
  "protectedFilePatterns": [],      // path globs never auto-pruned ("secrets/**")
  "tui": { "enabled": true },       // companion TUI panel (stats + report)
  "strategies": {
    "deduplication": { "enabled": true, "protectedTools": [] },
    "purgeErrors":   { "enabled": true, "turns": 4, "protectedTools": [] }
  }
}

Permissions: the tool's permission action is prune; gate it with normal V2 permission rules ({ "action": "prune", "effect": "allow" }).

Develop

npm install
npm run typecheck   # tsc --noEmit
npm test            # node --import tsx --test test/*.test.ts
npm run build       # tsup -> dist/

MIT. See LICENSE.