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

Annotations only give readOnlyHint and openWorldHint; the description adds substantial non-redundant behavior: the layer failed against false positives in open countries and is being rebuilt, so nothing is ever returned as blocked. It discloses the response shape (review object with reason, data date equal to the layer's window end, plus confirmed_block_layer window and per-country measured-domain coverage) — information the annotations and schema do not carry at all.

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 under-review status is front-loaded, which is the single most important fact, and each sentence contributes (status, return shape, interpretive warning, alternative). It is denser than necessary — the 'open countries / stricter rule' backstory and the 'Voidly's' branding could be trimmed without loss.

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 must carry the return values, and it does: review object fields, the layer window, and coverage. It also preempts the natural misinterpretation of an empty blocklist. For a single-parameter read tool in a degraded state, nothing material is missing.

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% and the single 'country' parameter is already documented in the schema with an ISO 3166-1 example. The description adds nothing about the parameter (e.g. whether unsupported countries error or degrade to unknown), so it meets but does not exceed the baseline.

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 names the resource (national blocklist layer) and states the current outcome precisely: it lists no domain as blocked and answers 'verdict unknown'. That is an unusual but genuine statement of purpose; a reader knows exactly what this call returns and why. It is not quite a 5 because the operative verb is negated ('lists no domain as blocked'), so the tool's positive function has to be inferred.

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?

It explicitly routes the agent away from this tool for citable censorship events: 'For citable censorship events use get_active_incidents.' It also gives an interpretive rule ('absence from any list is not evidence of access'), which prevents misuse. It stops short of saying when the tool IS worth calling (e.g. only to surface the review/reason metadata).

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