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

Annotations already declare non-read-only, non-idempotent, open-world and destructive behavior, so the safety profile is covered. The description adds genuine mechanism detail absent from the annotations: Google fetches the file server-side from media_url, so there is no upload step. It could go further on return values or rate limits, but the added fetch semantics are substantive.

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?

Four tight sentences, front-loaded with the core action and mechanism, then constraints, then the one parameter caveat. No filler and nothing repeated from the schema or annotations.

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 creation tool with no output schema and full annotation coverage, the description supplies the operative constraints an agent needs to succeed (URL reachability, format, size, category intent). Minor omissions remain, such as what the call returns or whether the created media id is needed for later deletion, but nothing critical blocks correct invocation.

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 100%, so a baseline of 3 would apply, but the description meaningfully enriches key parameters: media_url must be publicly reachable https with concrete size/dimension limits, and category gets intent-based guidance beyond the enum list. This adds value over the schema's terse field descriptions.

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 uses a specific verb+resource ('Add a photo or video to a Google Business Profile location'), immediately distinguishing it from siblings like google_business_media_list and google_business_media_delete. An agent knows exactly what the tool does without opening the 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?

It gives real usage constraints ('Use category COVER or LOGO only when you intend to change the profile header or logo') and excludes invalid inputs (no short-lived signed URLs, no localhost). It stops short of routing the agent against alternatives such as media_list or media_delete, which is the only gap.

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