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

Annotations already declare readOnlyHint=true, destructiveHint=false, and openWorldHint=false, so safety is covered. The description adds that results include thumbnail and status, which is genuine output context given no output schema exists. It does not mention ordering, pagination behavior, or what happens when the list is empty.

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, front-loaded with what is returned, then usage triggers, then the alternatives. No redundant restatement of the title or schema fields.

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 read-only, closed-world list tool with complete safety annotations and no output schema, the description covers purpose, return fields, and routing. The remaining gap is paging/cursor behavior for a tool whose defaults are page=0 and limit=12.

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 33% - only 'language' is documented, while 'page' and 'limit' carry defaults and bounds but no textual meaning. The description adds nothing about these parameters, so it fails to compensate for the coverage gap. Only the schema's own min/max values hint at paging semantics.

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 - 'Lists the avatars the user created or got' - plus scope ('on Ania') and returned fields ('thumbnail and status'). It explicitly separates itself from search_avatars, search_marketplace, and my_purchases, so an agent can route correctly without opening a 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?

Gives concrete trigger phrases ('my avatars', 'the avatar I made'), an anticipatory use case ('before opening one of theirs'), and names the alternatives for public catalogue browsing and purchases. Both when-to-use and when-not-to-use are covered.

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