get_download_url

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

Annotations cover only readOnly and openWorld, and the description adds substantial behavior beyond that: auth requirements per mode (none for source, CWA Basic for opds, reachable file entry for gateway), expiry semantics (expires_at unknown=null, available_until bound by local reuse window and upstream expiry), the meaning of status:link_issued, that repeated calls do not re-fetch the ticket, and that verification is server-observed. It is consistent with the annotations and materially richer than the structured fields.

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?

The content is dense and mostly earns its place, but it is delivered as one semicolon-chained paragraph that opens with the delivery:source detail instead of a defining first sentence. It is hard to scan and not front-loaded, which hurts selection speed even though little is truly wasted.

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?

An output schema exists, so return fields need not be explained, and annotations already carry the safety profile. The description still covers auth, expiry, status meaning, and the client-side follow-up required. It is nearly complete for a 2-param tool, with only the task_id provenance left implicit.

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 0%, so the description must carry the meaning. It explains all three delivery enum values in operational terms (source=default original file link, opds=authenticated link, gateway=signed time-limited GET), which is the key disambiguation. task_id is only implied via 'download_book task' context rather than explicitly defined, leaving a small gap.

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?

The description makes clear this tool resolves the downloadable URL for a task, with distinct delivery modes (source/opds/gateway). It never states its relationship to siblings like download_book or get_task as a routing rule, so an agent must infer when this is the right call versus those. Clear verb+resource, but no explicit sibling differentiation.

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?

It gives concrete when-to-use guidance per delivery mode: download_book tasks default to delivery:source, other tasks default to CWA-authenticated OPDS links, and delivery:gateway is an explicit request for a time-limited signed GET requiring a reachable file entry. It also notes the agent must still perform the HTTP save/read itself. No exclusion criteria relative to sibling tools, so not a full 5.

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