JoyD/pdf-reader-mcp/docs/performance.md

Performance

Performance is a key consideration for the PDF Reader MCP Server, as slow responses can negatively impact the interaction flow of AI agents.

Core Library: pdfjs-dist

The server relies on Mozilla's pdf.js (specifically the pdfjs-dist distribution) for the heavy lifting of PDF parsing. This library is widely used and generally considered performant for standard PDF documents. However, performance can vary depending on:

• PDF Complexity: Documents with many pages, complex graphics, large embedded fonts, or non-standard structures may take longer to parse.
• Requested Data: Extracting full text from a very large document will naturally take longer than just retrieving metadata or the page count. Requesting text from only a few specific pages is usually more efficient than extracting the entire text.
• Server Resources: The performance will also depend on the CPU and memory resources available to the Node.js process running the server.

Asynchronous Operations

All potentially long-running operations, including file reading (for local PDFs), network requests (for URL PDFs), and PDF parsing itself, are handled asynchronously using async/await. This prevents the server from blocking the Node.js event loop and allows it to handle other requests or tasks concurrently (though typically an MCP server handles one request at a time from its host).

Benchmarking (Planned)

(Section to be added)

Formal benchmarking is planned to quantify the performance characteristics of the read_pdf tool under various conditions.

Goals:

• Measure the time taken to extract metadata, page count, specific pages, and full text for PDFs of varying sizes and complexities.
• Compare the performance of processing local files vs. URLs (network latency will be a factor for URLs).
• Identify potential bottlenecks within the handler logic or the pdfjs-dist library usage.
• Establish baseline performance metrics to track potential regressions in the future.

Tools:

• We plan to use Vitest's built-in benchmarking (bench function) or a dedicated library like tinybench.

Benchmark results will be published in this section once available.

Current Optimization Considerations

• Lazy Loading: The pdfjs-dist library loads pages on demand when pdfDocument.getPage() is called. This means that if only metadata or page count is requested, the entire document's page content doesn't necessarily need to be parsed immediately.
• Selective Extraction: The ability to request specific pages (pages parameter) allows agents to avoid the cost of extracting text from the entire document if only a small portion is needed.

(This section will be updated with concrete data and findings as benchmarking is performed.)