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

Annotations already cover the safety profile (readOnlyHint=true, openWorldHint=false), and the description adds genuinely useful behavioral context by naming the return fields (blocking status, evidence sources, confidence, blocking method) and the detection techniques (DNS, TCP, TLS, HTTP). It omits caveats like snapshot vs. real-time detection or latency, which keeps it short of a 5.

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?

Two tightly written sentences with no filler; the purpose is front-loaded and the return-value detail follows compactly.

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?

There is no output schema, so the description carries the burden of describing return values, which it does by enumerating status, evidence, confidence, and method. For a simple two-parameter read operation with annotations covering safety, nothing critical is missing, though detection limitations are unstated.

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 schema already documents both parameters with examples. The description adds no syntax or format detail beyond what the schema provides, so the baseline 3 is appropriate.

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 verb ('Check') and resource ('a specific domain is blocked in a country'), and the blocking-method detail distinguishes it from siblings like check_service_accessibility or get_domain_timeline. An agent can identify the tool's function without opening the schema.

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?

Usage is implied by the name and description (check a domain's blocking status in a given country), but there is no explicit when-to-use, when-not-to-use, or routing to alternatives such as get_national_blocklist or check_service_accessibility. This is minimum-viable context.

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