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 compactionSnapcompactEngine 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);
