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

Annotations already declare destructiveHint=true and idempotentHint=true, so the safety profile is covered. The description adds value beyond them by disclosing the concrete consequence: compositions referencing the item will fail to render, plus explicit irreversibility. It does not mention auth/permission requirements or behavior on repeated deletion, which keeps it from a 5.

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?

Three short sentences, no filler, with the destructive nature stated first and the risk condition second. Every clause earns its place.

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 one-parameter destructive tool with no output schema and full annotation coverage, the description supplies the two things an agent most needs: irreversibility and downstream render impact. It omits how to obtain or verify a mediaItemId and behavior on re-deletion of an already-deleted item.

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% for the single mediaItemId parameter, so the schema carries the burden. The description adds no meaning (no format, source, or retrieval hint for the 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?

The description states a specific verb and resource ('Permanently delete a media item from your library') with the scope modifier 'permanently' front-loaded. It is trivially distinguishable from the other delete_* siblings (delete_brief, delete_composition, delete_project, delete_webhook) because the resource is named 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?

It gives a clear usage condition ('only delete media no composition still needs') and implies the cleanup context, which tells the agent when this is appropriate. It does not name an explicit alternative (e.g., a detach/replace tool) or a precondition check step, so it stops short of full when/when-not/alternatives guidance.

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