Get Spam Blacklist

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

Annotations already declare readOnlyHint=true, idempotentHint=true and destructiveHint=false, so the safety profile is covered. The description still earns credit for non-obvious behavior: wildcard syntax, case-insensitive matching, account-wide sharing of sender lists, and treating an empty 200 as an empty list. It does not describe ordering or pagination of the returned entries, which is the remaining behavioral gap.

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?

Four short sentences, each contributing a distinct fact, with the core purpose front-loaded before details about matching and list scope. No filler or repetition.

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 single-parameter read tool with full schema coverage, complete annotations, and an output schema that documents the return value, the description covers everything an agent needs: purpose, matching semantics, list scope, and empty-result behavior.

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%, so the domain format (letters, digits, hyphens, at least one dot) is already fully documented in the schema. The description's note that sender lists are shared across all domains on the account sharpens what the domain parameter does and does not scope, but that is a modest addition over a fully described single parameter.

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 spam blacklist entries for a domain"), which is enough to separate it from add_spam_blacklist_entry and remove_spam_blacklist_entry by name alone. It never explicitly contrasts itself with the sibling get_spam_whitelist, so the differentiation is implied 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?

The read-only listing framing implies when to use it, and the sibling names make the add/remove counterparts guessable. There is no explicit "use this when..." clause, no mention of when to prefer get_spam_settings, and no stated prerequisites.

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