download_crossref

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

It transparently states that the tool always returns a failure message because CrossRef does not support PDF downloads, fully disclosing the tool's behavior beyond any 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 concise with clear Args/Returns/Note sections, though it could be slightly shorter without losing clarity.

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 simple behavior (always fails), the description is complete, covering purpose, parameters, return value, and context. Adequate for a limited-function tool.

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 explains paper_id as a CrossRef DOI with an example, and save_path as a directory with default, adding meaning beyond the bare schema.

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 that the tool attempts to download a PDF from CrossRef but returns a message indicating it is not supported. This is specific and distinguishes it from other download tools that may succeed.

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 suggests using the DOI to access the paper through the publisher's website as an alternative, but it does not explicitly compare to sibling tools like download_scihub or provide when-to-use guidance.

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