download_pdf

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

With no annotations provided, the description carries the full behavioral burden and does so excellently. It discloses SSRF safety validation, PDF magic-marker verification, a 100 MB size cap, and atomic writes that prevent partial files. This goes well beyond typical descriptions and addresses security and reliability concerns.

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 two sentences, front-loaded with the primary purpose, and then efficiently packs usage guidance and safety details. Every sentence earns its place, with no filler or redundancy.

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?

The description covers purpose, prerequisite, safety, size limits, and failure behavior. The existence of an output schema means return values need no description. A slight gap is that it doesn't mention error handling for non-PDF content beyond the magic-marker check, but the given details are otherwise comprehensive for this tool's 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?

Schema description coverage is 100%, and the schema already explains each parameter (url, doi, filename) with useful context. The description adds no new parameter-level semantics; it only reinforces that the URL should come from find_oa_pdf. Per calibration, a baseline of 3 is appropriate when the schema covers parameters well.

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 function: 'Download a PDF to the local PDF directory.' This is a specific verb+resource+location combination. It also implicitly differentiates from siblings like find_oa_pdf by focusing on the download step, and explicitly references the typical prerequisite workflow.

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 explicit workflow guidance by instructing 'Use find_oa_pdf first to obtain a URL.' This tells the agent when to use this tool in sequence with a sibling. It lacks an explicit 'when not to use' clause, but the context is clear enough for a download tool.

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