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

The 'WRITE:' marker plus 'API: PUT /media' usefully discloses the mutation semantics that the annotations (only idempotentHint=true) omit. However, with a PUT it is unclear whether omitted fields are cleared or preserved, and there is no mention of required scopes, whether the change is reversible, or what errors occur — gaps that matter for a destructive write with no destructiveHint provided.

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 terse, front-loaded sentences with zero filler: the write intent and field scope come first, the endpoint second. Nothing could be cut without losing 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?

For a mutation tool with no output schema, no destructive/readOnly annotations, an undisclosed partial-update contract, and 86% of parameters undocumented in the schema, the description is too thin. It never says what is returned, whether absent fields are nulled, or what permissions are needed.

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 only 14% (just 'Media id.'), so the description carries real weight, and it does name six of the seven parameters. But it renames 'hidden' as 'visibility' and gives no meaning to the two enums (type, branding) or to defaults, leaving the agent to read the schema for anything actionable.

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 pairs a specific verb with a specific resource and enumerates the mutable fields (name, description, type, visibility, highlight, branding), so an agent immediately knows this is the single-item mutation tool. It also prefixed 'WRITE:' to separate it from the get_* and list_* siblings, though it never names a sibling explicitly.

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?

The scope ('of one media item') implies when the tool applies, but there is no explicit when-to-use guidance, no prerequisites, and no pointer to alternatives such as hdphotohub_set_site_media_order or hdphotohub_get_media for reading. Usage must be inferred from the field list.

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