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

Annotations already declare readOnlyHint=true, so the agent knows this is a safe read operation. The description adds meaningful behavioral context by specifying what the profile reports: source category, holdings extent, link-graph trust, and copy freshness. It does not contradict annotations and provides useful detail beyond a generic 'get info' statement.

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 short paragraphs with no filler: the first defines the tool's output dimensions, the second gives the decision-use context. The most important action ('Describe a site in the index') is front-loaded, and every sentence contributes information an agent needs.

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?

With one required parameter, a 100%-described schema, and readOnlyHint annotation, the tool is simple. There is no output schema, so the description appropriately carries the burden of explaining what the agent will receive: source type, holdings, trust, freshness. It also explains why this matters for evaluating claims. Nothing essential 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 schema describes host as 'Domain, e.g. cbr.ru' with an example. The description does not add substantial parameter-level meaning beyond calling it a site, but it does not need to because the schema already documents the only parameter clearly. 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 opens with a specific verb and resource: 'Describe a site in the index.' It then enumerates exactly what the profile contains (source type, holdings, link-graph trust, freshness), making its purpose unmistakable. This differentiates it from sibling search/fetch/list tools, which operate on URLs or results rather than profiling site trustworthiness.

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 description explicitly tells the agent when to use the tool: 'Use this before relying on a result.' It reinforces the decision with a concrete contrast between a ministry page and a forum post. It does not name alternative tools or exclusion cases, but the usage context is clear and actionable.

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