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

With no annotations, the description carries the full burden and does disclose the key trait: metadata is returned without transferring file contents, and it enumerates the returned fields (filename, access level, availability, existence, last-updated). It stops short of stating authentication requirements or what happens with an invalid/expired hash, so not a 5.

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 sentences, zero filler, with the scope-limiting clause ('without transferring file contents') front-loaded before the usage guidance. Every clause carries actionable information.

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?

No output schema exists, so the description compensates by naming the metadata fields returned, and the params are fully covered by the schema. Minor gap: no mention of authentication expectations in prose or behavior on an unknown/expired hash, which matters for a 'paid download' resource.

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 100%, so download_hash's origin ('Opaque download hash returned by list_downloads') and api_key's optionality are already documented in structured fields. The description reinforces the dependency on list_downloads but adds no format, constraint, or meaning beyond the schema — baseline 3.

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 and resource ('Fetch metadata for a specific paid download') and immediately delimits scope with 'without transferring file contents', which separates it from any content-download sibling. An agent can distinguish this from list_downloads or lookup tools without opening a schema.

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 names the prerequisite/alternative ('Use after list_downloads') and enumerates the user intents that should trigger it (suggested filename, access level, availability, file existence, last-updated time). Both the when and the preceding tool are given, leaving nothing to inference.

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