Tool Filter
Filters tools from upstream Multi-Modal Chat Protocol (MCP) servers using a regex-based deny list.
About
This proxy server addresses the critical issue of context pollution in large language models (LLMs) when interacting with Multi-Modal Chat Protocol (MCP) servers. Many LLMs currently fail to remove descriptions of denied or unused tools from their context, leading to significant token waste—potentially tens of thousands of tokens—and decreased efficiency. By acting as a transparent proxy, this tool effectively filters out unwanted or irrelevant tools based on regex-defined deny lists, ensuring that LLMs only receive necessary tool descriptions. This minimizes context engineering overhead and helps agents focus on relevant tasks without distraction from extraneous tool options.
Key Features
- Tool Filtering: Block specific tools using regex patterns
- Zero Latency: Cached tool list, minimal overhead
- Fail-Fast: Immediate error on connection issues or invalid patterns
- Transparent Proxying: Forwards allowed tool calls to upstream without modification
- 4 GitHub stars
Use Cases
- Minimizing LLM context pollution from unnecessary tool descriptions.
- Customizing the set of available tools for specific agent environments or tasks.
- Preventing LLM agents from accessing or being exposed to dangerous or irrelevant tools.
