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

Annotations already declare readOnlyHint=true, so the safety profile is covered. The description adds the media type enumeration and the underlying endpoint (GET /media), but says nothing about error behavior for a missing/invalid id or what a returned item contains.

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 short sentences, front-loaded with the verb and resource; nothing wasted. The "API: GET /media" clause is marginally redundant but cheap and aids traceability.

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 single-parameter read with annotations covering safety, this is minimally adequate. With no output schema, an agent still does not know what fields a media item returns or what happens on a bad id, which the description could have sketched in one clause.

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% and the `mid` property already documents its provenance ("from hdphotohub_get_site") plus positivity constraints. The description adds nothing beyond "by id", so the baseline 3 applies.

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 ("Get one media item... by id") and enumerates the resource types (photo, video, floor plan), which distinguishes it from list_* and update_media siblings. It does not explicitly name an alternative, but the retrieval-by-id semantics are 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?

There is no guidance on when to use this versus any sibling — e.g. how to enumerate ids first, or that update_media is the mutation counterpart. The only routing hint (that ids come from hdphotohub_get_site) lives in the schema, not the description.

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