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

Annotations already declare non-read-only, non-idempotent, non-destructive behavior; the description adds genuinely new context by disclosing that the created asset is auto-named with the photographer credit and what the call returns. It does not address what happens on repeat adds of the same photo (relevant given idempotentHint=false), which is the one behavioral gap.

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 tight sentences: the action and naming behavior come first, the return value second. Every clause carries information and nothing is repeated from the title.

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?

There is no output schema, and the description compensates by naming the returned fields (media_uid, url) and their downstream use. Combined with the 100%-covered input schema, an agent has everything needed to invoke and chain this tool correctly.

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 schema descriptions already explain that id and provider come from search_stock_photos, so the description mostly echoes that provenance. It adds no syntax, enum, or formatting detail beyond the schema, so baseline 3 is appropriate.

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 ('Copy a photo ... into the Media Library'), names the source tool (search_stock_photos), and implies the destination collection. This distinguishes it clearly from add_media_from_url (URL-sourced) and generate_image (AI-generated) without needing to open any 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 ties input to the upstream step ('a photo found with search_stock_photos') and points to the downstream use ('for create_post media_uids'), so the agent knows the workflow position. It does not explicitly state when to prefer add_media_from_url or generate_image instead, so it stops short of full alternative routing.

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