GlyphCompress — Semantic Token Compression
Compress the context your IDE sends to an LLM — file contents, diagnostics, chat history, diffs — using a compositional glyph system, so you spend fewer tokens per request without losing the information the model needs to help you.
A shared codebook is injected once into the system prompt so the model can decode the compressed glyphs back into full concepts. Compression is calibrated against real provider tokenizers (OpenAI's cl100k_base/o200k_base) rather than character-count heuristics, so reported savings are real, measured token reductions — not guesses.
What this extension does
- Compress Selection: compress the currently selected text/code and copy the result to your clipboard.
- Ask LLM (Auto-Compress): automatically compress context before it reaches VS Code's built-in Language Model API (Copilot Chat and compatible extensions), with zero manual steps.
- Zero-Command Transparent Proxy: a local proxy that sits between your IDE (Cursor, Continue, Cline, and other OpenAI/Anthropic/Gemini-compatible tools) and the real provider API, compressing every request automatically. Point your IDE's API base URL at
http://localhost:8080 and nothing else changes.
- Build Project Codebook: scan your workspace to rank files by relevance to a task and build a persistent index used by the Context Router.
- Compress Entire Workspace: batch-compress every open/relevant file at once.
- Show Compression Stats / status bar: live token-savings numbers for your current session.
Providers and trust policies
Works with OpenAI, Anthropic Claude, Gemini, and Antigravity — each has its own compression profile, calibrated separately since tokenizers behave differently across providers.
Trust policies control what compression is allowed to do to your data:
| Policy |
Reversible |
What it allows |
lossless |
Yes |
No lossy transforms at all |
reversible |
Yes |
Prompt patterns, tech names, file paths, diagnostics, dynamic dictionary |
privacy |
Yes |
Everything in reversible, plus redaction of API keys, tokens, emails, and IPs before compression |
lossy |
No |
Everything, including code minification, structural summaries, and redundancy stripping |
When a level/policy combination allows something irreversible (like ultra-level code summarization), the extension surfaces a plain-language trust warning in its output channel — derived directly from what that policy actually permits, not a guess about how the model will behave.
Settings
| Setting |
Default |
Purpose |
glyphCompress.enabled |
true |
Enable/disable compression |
glyphCompress.provider |
auto |
auto, raw, openai, anthropic, antigravity, gemini, local |
glyphCompress.compressionLevel |
standard |
light, standard, aggressive, ultra, auto (auto picks per request) |
glyphCompress.trustPolicy |
auto |
lossless, reversible, privacy, lossy |
glyphCompress.targetApiUrl |
https://api.openai.com |
Upstream API the proxy forwards to |
glyphCompress.showStatusBar |
true |
Show live compression stats in the status bar |
glyphCompress.experimentalDecay |
false |
Progressively compact older chat history for long-running conversations |
glyphCompress.holographicFolding |
false |
Group overlapping related files and shared imports into layered blocks |
glyphCompress.intentDiffs |
false |
Condense verbose diffs into short, declarative change-action lines |
Also available as
- CLI:
npx glyph-compress <file> — same engine, usable outside VS Code, plus route/team-codebook/inspect/doctor commands.
- MCP server:
npx glyph-compress-mcp — use GlyphCompress from Claude Code, Claude Desktop, or any other MCP-compatible client.
- Library:
npm install glyph-compress for direct GlyphCompressor/wrapOpenAI/wrapAnthropic usage in your own code.
Links
Dual-licensed: AGPL-3.0 for open-source use, commercial license available for proprietary use.
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