Custom PDF MCP Server

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

With no annotations provided, the description carries the full burden of behavioral disclosure. It mentions the tool returns a dictionary of PDF metadata, which is helpful, but lacks details on error handling (e.g., for invalid paths), performance characteristics, or any side effects. This is a significant gap for a tool that interacts with file systems.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is appropriately concise and well-structured, with a clear purpose statement followed by Args and Returns sections. Every sentence adds value, though it could be slightly more efficient by integrating the path requirement into the purpose statement.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

Given the tool's moderate complexity (file I/O operation), lack of annotations, and no output schema, the description is minimally adequate. It covers the purpose and parameter semantics but misses usage guidelines and detailed behavioral context, leaving gaps for the agent to infer.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

The description adds meaningful context beyond the input schema, which has 0% coverage. It specifies that 'file_path' must be an absolute path to a PDF file, clarifying the parameter's semantics and constraints. Since there's only one parameter, this adequately compensates for the schema's lack of description.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The description clearly states the tool's purpose as '获取PDF文件的基本信息' (get basic information of PDF files), which is a specific verb+resource combination. However, it doesn't explicitly differentiate from sibling tools like 'list_pdfs_in_directory' (which lists files) or 'read_pdf_text' (which extracts content), so it falls short of a perfect score.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description provides no guidance on when to use this tool versus alternatives. It doesn't mention the sibling tools or clarify scenarios where this tool is appropriate (e.g., for metadata extraction rather than content reading or file listing). This leaves the agent with insufficient context for tool selection.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.