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

With no annotations, the description carries the full burden and discloses almost nothing: no auth requirement, no pagination or ordering, no indication of whether addresses and domains are separate fields. It does implicitly signal an account-scoped read, which is the only behavioral clue offered.

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?

Extremely short with no waste, but it is a sentence fragment lacking a leading verb, and it is under-specified rather than genuinely concise. Front-loading is trivially satisfied because there is only one clause.

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 no-annotation, no-output-schema tool, the description should at least say what the returned entries look like or how they are scoped. Neither is provided, leaving the agent to guess at the response shape and filtering 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?

The tool takes zero parameters, so the schema imposes nothing to explain and the baseline of 4 applies. The description's brief statement of what is returned is the only parameter-adjacent content and it is adequate.

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 fragment 'The account's blocked addresses and domains' identifies the resource returned but supplies no verb, so the agent must infer that it lists existing blocks rather than creating them. Given siblings like block and unblock, that inference is easy but not stated. Purpose is implied rather than declared.

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?

No when-to-use guidance, no mention of block/unblock as the mutation alternatives, and no indication of scope conditions. The read-only listing intent is only inferable from the noun phrase.

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