Download MyChart Test Result as PDF

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

Annotations provide readOnlyHint=false, destructiveHint=false, and idempotentHint=true, and the description adds context beyond those: files are saved to a specific directory (~/.mychart-mcp/downloads), the PDF is rendered from the result detail page, and login is required. It also describes the return value shape, which helps the agent understand side effects and outcomes without contradicting the annotations.

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 compact and well-structured: a one-sentence purpose, a short prerequisites note, a bulleted argument list, a storage location line, and a return shape line. Every sentence contributes meaningful information, and there is no redundant or filler content.

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?

For a tool with only two parameters, no output schema, and existing annotations, the description covers all essential contextual aspects: what it does, prerequisites, where files are saved, the output format, and how to source the result_id. It does not explain error handling, but that is not necessary for a straightforward download tool of this complexity.

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 schema already describes both parameters with 100% coverage, so the baseline is 3. The description adds value by specifying that result_id can be a full URL (already in schema) and by giving the default filename pattern ('<date> <test name>.pdf'), which is not in the schema and clarifies how the optional filename parameter behaves.

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 opens with a specific verb and resource: 'Save one test result as a PDF file on disk,' which clearly states what the tool does and its output format. It also differentiates from siblings by noting the result_id comes from mychart_list_test_results and that it renders from the result detail page, making it distinct from screenshotting or retrieving test result data.

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 clearly states a prerequisite ('Requires a logged-in session'), which indicates when the tool can be used. It does not explicitly name alternatives or when-not-to-use scenarios, but the context of 'PDF file on disk' and the referenced sibling tools make the appropriate usage clear.

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