download_file

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

Annotations declare readOnlyHint=true and destructiveHint=false, so tool is safe. Description adds value by explaining content_type behaviors (text, pdf_text, binary_url), file size limit >1MB triggers binary_url, and that download_link is only present for binary_url. This is rich behavioral context beyond 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?

Well-structured with clear sections: purpose, usage order, return fields, content_type enumeration. Some minor redundancy (file_name explained twice), but overall efficient for the level of detail provided.

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?

Complete for a read-only file download tool. Covers all necessary usage: prerequisite get_row, file selection, content types, return fields, edge cases (external URLs, large files). No output schema exists, but description comprehensively documents return structure.

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 has 100% description coverage, so baseline is 3. Description adds significant value: clarifies file_name optionality (omission uses first file), explains behavior of different content types, and describes return structure. This far exceeds the schema alone.

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?

Describes exactly what the tool does: reads content of a file attached to a row in a file/image column. Distinct from upload_file (write) and get_row (which only sees file metadata). Clear verb+resource+scope.

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?

Explicitly tells when to use: after get_row to see available files; how to select a specific file by name; explains that omitting file_name uses first file. Sibling upload_file is inverse operation, clearly distinguishable.

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