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

Annotations already declare readOnly, idempotent, non-destructive and closed-world, so the safety profile is covered. The description adds genuinely new behavior: only *published* assets are returned, and the response will contain URL, content type and size.

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 sentences, zero filler, front-loaded with the purpose and then the use case. Nothing in it could be removed 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?

Both optional identifiers are documented in the schema, an output schema covers the return shape, and annotations cover safety semantics. The description's extra job — telling the agent it only sees published assets — is done.

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 each parameter already documents the 'provide this or the other' rule, so the schema does the heavy lifting. The description adds mild value by restating that lookup can be by slug or media id, but no format examples or clarification of precedence is given.

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 a single published asset') plus the two lookup keys and what is returned (CDN URL, content type, size). The word 'single' and 'published' clearly separate it from list_assets and the rest of the get_* family.

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 says when to reach for it: 'Use this to confirm an asset exists and fetch the URL to embed.' It gives a positive use case but does not name an alternative (e.g. list_assets for discovery) or state exclusions.

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