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

Annotations already declare readOnly, idempotent, closed-world and non-destructive, so safety is covered. The description adds two genuine behavioral facts: the call is free (no quota/credit cost) and it returns the full paid-file set with no filtering. It does not address result size, pagination, or cost of handling a bulk listing.

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?

One compact sentence with the scope up front and no filler. The leading fragment 'Free.' is slightly cryptic out of context but is a meaningful cost signal, not padding.

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?

With no output schema, the description usefully names the returned fields (sha256, size), which is the key compensating detail. It still leaves open how a bulk 'every paid file' response is shaped or bounded, which matters for an unfiltered listing 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?

Zero parameters, so the baseline of 4 applies. The description correctly implies no filtering or selector arguments, matching an empty 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 resource and return content: sha256 and size for every paid file. The scope ('every paid file') makes it distinguishable from the sibling checklist/TOC/preview tools, though the note that it mirrors GET /checksum is developer-facing rather than selection-relevant.

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?

No when-to-use or when-not-to-use guidance, and none of the siblings are referenced. The agent must infer that this is the integrity-verification path rather than the manifest/checklist path; 'every paid file' is the only usage signal.

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