Show HN: MCP tools do parallelize in Claude Code (study with raw data) (github.com)

A recent study revealed that the Multi-Channel Protocol (MCP) tools within Claude Code can achieve significant parallelization when the server is configured with the `readOnlyHint: true` annotation. This configuration effectively doubles the parallel dispatch rate compared to the default setting of `readOnlyHint: false`, which results in serialized execution. The findings highlight that read-only operations benefit from parallelism, making the system more efficient and capable of handling tasks concurrently. The study presented quantitative evidence that under the right conditions, tools like `read_text_file` and `list_directory` demonstrated improved performance, with only a minimal increase in inter-process communication (IPC) overhead. This discovery is significant for the AI and machine learning community as it emphasizes the importance of correctly annotating tools for optimal server performance. By understanding that execution can be tailored for either parallel or serial processing based on specific tool annotations, developers can improve the efficiency of their models in real-world applications. The research utilized Claude Code v2.1.39 with Sonnet 4.0 and included multiple iterations to validate the performance claims, ultimately encouraging broader adoption of these practices in MCP server implementations to enhance execution efficiency.