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

Goes well beyond the readOnly/idempotent annotations by disclosing batch limits (20 paths, 40,000 chars), pagination via offset/next_offset, and how different media are returned (inline images, 10-minute download links for PDFs/larger images). These are operationally critical behaviors an agent cannot infer from the annotations or schema.

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?

Front-loads the core action and scope, then layers limits, pagination, media handling, and exclusions in a tight sequence. Every sentence carries distinct operational information with no filler.

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 an output schema exists, return values needn't be detailed, yet the description still explains the image/PDF return shapes and download-link lifetime. Combined with the limit and exclusion rules, an agent has everything needed to invoke correctly.

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 coverage is already 100%, so the baseline is 3, but the description adds meaning beyond it: the 40,000-char reply cap and the fact that offset resumes paths[0] from next_offset clarify how batching and pagination interact. It stops short of 5 since most per-parameter semantics are already in the 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?

States a specific verb (returns contents) and resource (files from a free public kit), scoped by 'path from the kit's file index' and limited to free/public kits. It differentiates from siblings by implicit scope (get_kit = metadata, this = file contents) but never names a sibling or explicitly contrasts with them.

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?

Clear context with exclusions: files of paid kits and step instructions of run kits are not returned, and paths must come from the kit's file index. It lacks explicit 'use X instead when...' routing against get_kit or search_kits, so it stops short of full alternative guidance.

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