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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive, closed-world), so the description's added value is semantic: blocking is suffix-wide (example.com covers blog.example.com) and already-emailed sites are deliberately excluded from the list. That exclusion is a non-obvious behavioral trait an agent could not derive from the schema or annotations.

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 the tool returns before qualifying semantics. The parenthetical example is justified because subdomain coverage is counter-intuitive; the 'never emailed again anyway' clause is slightly chatty but carries real information about list contents.

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 and no output schema, the description explains what is and is not in the list, which is the main thing an agent could mis-infer. It omits any mention of ordering, volume, or pagination, which is a minor gap for a list tool.

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% and the single workspaceId parameter is fully documented in the schema, including how to discover it via get_status. The description adds nothing about the parameter, so the baseline 3 for schema-covered parameters applies.

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 exactly what the tool returns — the domains blocked for the current site — which is a clear resource and scope even though it uses a noun phrase rather than an explicit verb. It does not, however, name or contrast itself with the sibling block_domains/unblock_domains tools that operate on the same data.

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?

There is no when-to-use or when-not-to-use guidance, and no routing to alternatives such as block_domains or unblock_domains. The agent must infer from the name and the readOnlyHint that this is the read counterpart, which is the whole of the guidance available.

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