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

Annotations already declare readOnlyHint=true and destructiveHint=false, so the safety profile is covered. The description adds useful context that the tool answers without an API key and that it covers whois/bgp history, but it does not disclose anything about output format, limits, or behavior for unknown indicators.

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 description is two sentences, front-loads the core purpose, and includes a compact example call. Every piece contributes useful information, and there is no redundant restating of the tool name or schema.

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 simple, read-only, single-parameter lookup tool with strong annotations, the description provides enough to call it correctly: purpose, indicator scope, authentication requirement, and an example. A brief note on the return format would be beneficial since there is no output schema, but this is a minor gap.

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 input schema already provides 100% coverage of the single parameter, describing valid indicator types. The description adds a concrete example call but no new semantic detail about the parameter itself, so it meets the baseline without going beyond it.

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 clearly states the resource ('historical records for an indicator') and gives concrete data types (whois/bgp history), so an agent can tell this apart from a generic lookup. It does not explicitly name or contrast a sibling tool, which keeps it from a 5, but the intent is unambiguous.

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 gives clear context: use this when historical indicator records are needed, and it notes that no API key is required. However, it does not explicitly say when NOT to use it or which sibling tools to prefer for other kinds of lookups, so the guidance is implied rather than explicit.

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