TokenSaver MCP
An MCP server that reduces AI API costs by up to 97% through token measurement, compression, caching, and pruning, all without changing prompts.
README
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TokenSaver MCP
Cut your AI API costs by up to 97% — without changing a single prompt.
An MCP (Model Context Protocol) server that gives AI agents ten tools to measure, compress, cache, and prune token usage — so developers on limited plans can do more with less.
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Why TokenSaver?
Every API call sends more tokens than necessary. Conversation history accumulates. Web pages arrive as raw HTML. Tool results get re-fetched on every turn. System prompts bloat over iterations.
TokenSaver intercepts each of these patterns and fixes them at the agent level — no model changes, no prompt engineering, no plan upgrades.
| Scenario | Before | After | Saved |
|---|---|---|---|
| 10-turn conversation history | 40,000 tokens | 8,000 tokens | 80% |
| Webpage fetch (raw HTML) | 22,000 tokens | 1,200 tokens | 94% |
| Bloated system prompt | 600 tokens | 220 tokens | 63% |
| Repeated tool call (cached) | 1,500 tokens | 50 tokens | 97% |
Tools
| Tool | What it does |
|---|---|
count_tokens |
Measure token cost before sending — decide whether to compress first |
compress_context |
Shrink long text or conversation history with offline LSA summarization |
cache_store / cache_get / cache_invalidate |
Persist tool results to disk with TTL — never run the same lookup twice |
extract_webpage |
Fetch a URL and return only the readable content, not raw HTML |
summarize_file |
Get a structural + content summary of any file or directory |
prune_conversation |
Remove filler turns and compress old messages in conversation history |
optimize_prompt |
Shorten verbose system prompts while preserving constraints |
advise_context_window |
Diagnose token bloat and get targeted recommendations |
All tools work fully offline — no API key required for core features.
Installation
git clone https://github.com/pozii/tokensaver.git
cd tokensaver
pip install -e .
Python 3.11+ required. On first use,
compress_contextwill auto-download the NLTKpunkt_tabtokenizer (~2 MB) if not already present.
How it connects to your AI client
TokenSaver has no URL and runs no background server by default. It uses stdio transport: the AI client reads your config, spawns python -m tokensaver as a child process, and talks to it through stdin/stdout. You never open a port or start anything manually — the client does it for you when it launches.
Your AI client ──spawn──▶ python -m tokensaver ──stdio──▶ tools available
The alternative is SSE transport, where you start the server yourself on a local port and the client connects over HTTP. This is useful for multi-agent setups or when multiple clients share the same server instance.
Setup
Claude Desktop
Config file location:
- macOS:
~/Library/Application Support/Claude/claude_desktop_config.json - Windows:
%APPDATA%\Claude\claude_desktop_config.json
{
"mcpServers": {
"tokensaver": {
"command": "python",
"args": ["-m", "tokensaver"]
}
}
}
Save the file and restart Claude Desktop. The tokensaver tools will appear in the tool list.
Claude Code
claude mcp add tokensaver -- python -m tokensaver
Or add manually to ~/.claude/settings.json:
{
"mcpServers": {
"tokensaver": {
"command": "python",
"args": ["-m", "tokensaver"]
}
}
}
OpenCode
Config file: ~/.config/opencode/config.json
{
"mcp": {
"servers": {
"tokensaver": {
"type": "local",
"command": ["python", "-m", "tokensaver"]
}
}
}
}
Any MCP-compatible client (SSE mode)
Start the server once:
python -m tokensaver --transport sse --port 8765
Then point your client at:
http://localhost:8765/sse
Fixing Python path issues
If your system has multiple Python versions and python resolves to the wrong one, use the full path:
# Find the right Python
which python3 # macOS / Linux
where python # Windows
Then use the full path in your config:
{
"mcpServers": {
"tokensaver": {
"command": "/usr/local/bin/python3",
"args": ["-m", "tokensaver"]
}
}
}
{
"mcpServers": {
"tokensaver": {
"command": "C:\\Python314\\python.exe",
"args": ["-m", "tokensaver"]
}
}
}
Usage
Recommended workflow
Each turn:
1. count_tokens → How large is my current context?
2. advise_context_window → Am I approaching the model's limit?
Before expensive tool calls:
3. cache_get → Did I already run this?
When fetching web content:
4. extract_webpage → Clean text, not raw HTML
When history grows long:
5. prune_conversation → Drop filler turns, compress old ones
6. compress_context → Shrink large injected context blocks
When writing system prompts:
7. optimize_prompt → Remove redundant phrasing
Tool reference
<details> <summary><strong>count_tokens</strong> — measure before you send</summary>
{
"content": "Some long text or list of messages...",
"model": "claude-sonnet-4",
"include_message_overhead": true
}
Returns token_count, encoding_used, model. Accepts a plain string or an OpenAI-format message list.
</details>
<details> <summary><strong>compress_context</strong> — shrink long text</summary>
{
"text": "3,000-token context block...",
"target_tokens": 600,
"mode": "extractive"
}
extractive (default) uses LSA sentence ranking — free, offline, no API call.
abstractive uses claude-haiku for higher quality — requires ANTHROPIC_API_KEY.
Returns compressed, original_tokens, compressed_tokens, reduction_pct.
</details>
<details> <summary><strong>cache_store / cache_get / cache_invalidate</strong> — skip repeated work</summary>
# Standard pattern: check before running
key = cache_key("extract_webpage", {"url": "https://example.com"})
hit = cache_get(key=key)
if not hit["hit"]:
result = extract_webpage(url="https://example.com")
cache_store(key=key, value=str(result), ttl_seconds=3600)
Cache is stored on disk at ~/.tokensaver/cache/ and survives server restarts.
</details>
<details> <summary><strong>extract_webpage</strong> — content, not markup</summary>
{
"url": "https://example.com/article",
"max_tokens": 2000,
"include_links": false,
"include_metadata": true
}
Uses trafilatura with BeautifulSoup as fallback. Returns content, title, token_count, truncated.
</details>
<details> <summary><strong>summarize_file</strong> — understand code without reading it all</summary>
{
"path": "/home/user/myproject",
"mode": "both",
"max_tokens": 500,
"file_extensions": [".py", ".md"],
"max_depth": 3
}
mode options: "structure" (tree only), "content" (summarized text), "both".
</details>
<details> <summary><strong>prune_conversation</strong> — clean up history</summary>
{
"messages": [...],
"max_output_tokens": 2000,
"keep_last_n": 4,
"prune_strategy": "hybrid"
}
"remove" drops filler turns ("Sure!", "Got it.").
"compress" summarizes older turns in place.
"hybrid" does both — recommended for most cases.
Returns the pruned messages list, original_tokens, pruned_tokens, counts of removed/compressed turns.
</details>
<details> <summary><strong>optimize_prompt</strong> — shorter system prompts</summary>
{
"prompt": "Please make sure to always answer questions...",
"optimization_level": "medium",
"preserve_constraints": true,
"output_format": "prose"
}
"light" removes filler phrases. "medium" deduplicates sentences. "aggressive" restructures.
preserve_constraints: true always keeps sentences containing never, must, always, do not.
</details>
<details> <summary><strong>advise_context_window</strong> — know what to fix</summary>
{
"model": "gpt-4o",
"current_tokens": 110000,
"messages": [...],
"target_utilization": 0.75
}
Returns status ("ok" / "warning" / "critical"), headroom_tokens, prioritized recommendations, and a per-turn breakdown sorted by token cost.
Supports: GPT-4o, GPT-4o-mini, Claude 3–4 series, Gemini 1.5/2.0/2.5, O1/O3, Llama 3, Mistral.
</details>
Optional: LLM-backed summarization
For higher-quality abstractive compression on very large texts (>5,000 tokens):
pip install "tokensaver-mcp[llm]"
Set ANTHROPIC_API_KEY in your environment or a .env file, then use mode: "abstractive" in compress_context.
Running Tests
pip install -e ".[dev]"
python -m pytest tests/ -v
38 tests — all offline, no API key or network required.
Project Structure
src/tokensaver/
server.py # FastMCP app, tool registration
models.py # Context window table, shared types
tools/
counter.py # count_tokens
compress.py # compress_context
cache.py # cache_store / cache_get / cache_invalidate
extractor.py # extract_webpage
summarizer.py # summarize_file
pruner.py # prune_conversation
optimizer.py # optimize_prompt
advisor.py # advise_context_window
utils/
token_utils.py # tiktoken wrapper
text_utils.py # sentence splitting, deduplication
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