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

No annotations are provided, so the description carries the full burden. It does disclose a meaningful trait, that nothing is stored/uploaded, which reassures the agent this is a non-mutating check, but it says nothing about auth requirements, rate limits, or whether the target file is fetched or uploaded.

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?

Two compact sentences with zero filler, front-loading the core action and scope before the conditional convert behavior.

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 6-parameter tool with no output schema and no annotations, the description leaves notable gaps: it never states the result shape (pass/fail detail), how the file is supplied (mutual exclusivity of source_url vs data_base64), or what filename is for. The ttl-on-a-check-tool oddity is also unexplained.

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 83%, giving a baseline of 3, and the description adds genuine meaning for the convert parameter by explaining that it reports whether cropping or padding can fix the file. It doesn't clarify the relationship between source_url and data_base64 or the ttl field, but it does go beyond the schema for the key behavioral param.

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?

Specific verb ('check a file') plus resource (a file against a target platform), and 'without storing it' cleanly distinguishes it from the upload_media sibling. It stops short of naming alternatives, but the purpose is unambiguous.

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?

Usage is only implied: validating without persisting suggests a pre-upload check, and the mention of convert hints at a second use case. There is no explicit when-to-use/when-not or prerequisite statement.

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