Get Avatar Image by ID

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

Annotations already cover readOnlyHint, openWorldHint, and idempotentHint, so the safety profile is handled by structured data. The description adds only an efficiency trait and confirms image retrieval; it does not disclose error behavior (e.g., 404 responses) or response format, which are minor gaps given the annotation coverage.

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?

The core purpose and efficiency guidance are front-loaded in two succinct sentences before the examples block. The examples are slightly redundant ('Get the avatar image for this Gravatar ID' restates sentence one) but they serve natural-language intent matching, so the structure remains efficient.

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 5-parameter tool with full schema coverage and three strong annotations, the description covers the essentials: what it does, the key input, and a usage hint. It could be improved by explicitly routing to get_avatar_by_email when only the email address is known, but nothing required for a correct call is missing.

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%, so all five parameters are already documented in the schema. The description adds marginal value by linking 'hashed identifier' to avatarIdentifier and hinting at size usage via the '150px' example, but these largely echo existing schema text.

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 action ('Retrieve the avatar image') and resource ('Gravatar profile using an avatar identifier'), which is clear. It differentiates from get_avatar_by_email through the efficiency note and the identifier-based retrieval key, but it never names the sibling explicitly, so the differentiation is implicit rather than stated.

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?

'More efficient when you already have the hashed identifier' provides a concrete when-to-use signal and implies the alternative lookup path (by email) when the hash is not on hand. However, it stops short of explicitly naming get_avatar_by_email or stating a formal when-not-to-use exclusion.

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