Get Avatar Image by Email

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

The description discloses the important preprocessing behavior of automatic email normalization and hashing before the Gravatar API call, which is not captured by the annotations. The readOnlyHint, openWorldHint, and idempotentHint already cover safety, so the extra detail about hashing is meaningful rather than redundant. It doesn't discuss return format or fallback behavior, but those are partly covered by the schema.

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 description is two substantive sentences plus a compact examples block; the main action and the critical hashing behavior are front-loaded. No filler or repetition of schema details, so every sentence 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?

The schema and annotations cover parameter details, safe read-only behavior, and idempotency, while the description supplies the purpose, lookup method, and normalization behavior. With no output schema, a brief mention of the return format (e.g., image bytes vs. URL) would improve completeness, but this is a minor gap because the tool name and examples make the image result clear. Overall it is sufficiently complete for an agent to invoke 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?

With 100% schema description coverage, the schema already documents all five parameters, including enums and size bounds, so the description doesn't need to repeat them. The only added parameter-related value is the note that email is normalized and hashed, which supplements the email parameter's schema text. This matches the baseline of 3 for a fully covered schema.

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 uses a specific verb ('Retrieve'), a precise resource ('avatar image for a Gravatar profile'), and the key lookup method ('using an email address'), which distinguishes it from sibling tools like get_avatar_by_id and get_profile_by_email. This gives an agent a clear basis for selecting the correct tool.

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?

The description implies use when an email address is available and an avatar image is wanted, and the examples reinforce natural-language triggers. However, it never explicitly states when not to use it or points to alternatives such as get_avatar_by_id when an ID is available, so usage guidance remains mostly implicit.

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