JessenReinhart/dsh-snapcompact

Bitmap-frame context compression plugin for DeepSeek Harness (DSH).

Inspired by @oh-my-pi/snapcompact.

Instead of asking an LLM to summarize discarded conversation history in lossy prose, snapcompact serializes the exact conversation and renders the text into dense PNG frames of pixel-font glyphs that vision models read back directly. The entire process is local, fast, and deterministic — no auxiliary LLM API calls, no summarization latency, and zero token-cost overhead beyond the compact bitmap frames.

Features

• Local & Deterministic: High-throughput rasterization using native pixel-font rendering (@oh-my-pi/pi-natives).
• Provider-Aware Shapes:
  • anthropic (11on16-bw): 8x13 font on 11px advance, black-and-white.
  • google (8on22-bw): 8x13 font on 22px pitch, tuned for Gemini vision budget.
  • openai (8on22-bw): 8x13 font on 22px pitch, sent with detail: "original".
  • cjk (silver16-bw): Silver TrueType font on 16x16 grid for East Asian (Chinese, Japanese, Korean) text.
• Structured Transcript Serialization:
  • ¶user: user message sections
  • ¶think: assistant reasoning blocks
  • ¶ai: assistant message sections
  • ¶call: name(args)//intent tool calls with parameters
  • <out>...</out> formatted tool results with dimmed noise
  • Automatic FILES section tracking read and modified files ((Read), (Write), (RW))
• DSH Attachment Integration:
  • Renders PNG frames and persists them through ctx.attachments.saveImages
  • Fully compatible with DSH session persistence and replay
• Command & Service Support:
  • /snapcompact [--frames <N>] [--shape <name>] [--all] command for on-demand manual compaction
  • SnapcompactEngine implements the standard DSH CompactionEngine service
  • Automatic step-pressure compaction on agent/pre-step
  • Automatic context-overflow recovery on agent/request-error

Installation

1. Clone into DSH Profile

Clone the repository into your active DSH profile's packages/ directory (e.g. desktop):

# Windows PowerShell
git clone https://github.com/JessenReinhart/dsh-snapcompact.git "$env:USERPROFILE\.dsh\profiles\desktop\packages\dsh-snapcompact"

# macOS / Linux
git clone https://github.com/JessenReinhart/dsh-snapcompact.git ~/.dsh/profiles/desktop/packages/dsh-snapcompact

2. Register Bundle in Profile Configuration

Add packages/dsh-snapcompact to dsh.profile.bundles in your profile's package.json (e.g. ~/.dsh/profiles/desktop/package.json):

{
  "dsh": {
    "profile": {
      "bundles": [
        "packages/dsh-snapcompact"
      ]
    }
  }
}

The plugin automatically mounts its Cordis row via the bundled cordis.patch.yml.

3. Native Rasterizer

Snapcompact uses the high-performance native pixel-font rasterizer binary (pi_natives.<platform>.node).

The plugin automatically discovers this binary from any of:

• ~/.omp/natives/<version>/pi_natives.<platform>.node
• ~/.bun/install/cache/@oh-my-pi/pi-natives-*
• Environment variable override: PI_NATIVES_PATH=/path/to/pi_natives.<platform>.node

4. Restart DSH

Restart DeepSeek Harness to load the profile bundle. In chat, test with:

/snapcompact status

Usage

Commands

In any DSH session chat:

• /snapcompact — Archive older history immediately using smart defaults (auto shape, max 8 frames, retains 16% recent tokens in plain text).
• /snapcompact auto — Toggle automatic background compaction when the agent is idle.
• /snapcompact auto on — Enable automatic idle compaction.
• /snapcompact auto off — Disable automatic idle compaction.
• /snapcompact auto threshold <pct> — Set context window threshold percentage to trigger idle compaction (default 80%).
• /snapcompact status — Display current configuration, threshold, and live session token usage.
• /snapcompact --frames <N> — Archive history with custom maximum frame count.
• /snapcompact --shape <name> — Archive history with specific font/shape variant (11on16-bw, 8on22-bw, silver16-bw).
• /snapcompact --all — Archive all eligible history without retaining recent plain text.

Persistence

Auto-compaction preferences are saved to ~/.dsh/snapcompact-config.json and persist across sessions and application restarts.

Programmatic Compaction

const snapcompact = ctx.get("snapcompact");
await snapcompact.compactNow(agent, signal);