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

Even with no annotations, the description fully discloses behavioral traits: append-only change-log, one row per observed change plus daily heartbeat, the honest interpretation of 'first_recorded', the start date (2026-08-04), and the zero-rows behavior for unverified domains. This exceeds what annotations typically provide and gives clear expectations about data completeness.

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 well-structured: it opens with the core purpose, then details the data composition, and finally explains honesty semantics and edge cases. While it is longer than strictly necessary, each sentence adds meaningful context—such as what the tuple contains and the zero-rows behavior—so it earns its place.

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 tool with one parameter and no output schema, the description is quite comprehensive. It explains what data the history contains, the semantics of timestamps, and the behavior for unverified domains. It could be improved by briefly indicating the output format (e.g., list of change-log rows), but the description covers the most important context.

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 description does not explicitly explain the 'domain' parameter, but it repeatedly references domains ('every domain verify', 'a domain nobody has verified'), implying that the parameter is the domain to look up. Since the schema has no description and coverage is 0%, the description should compensate more, but for a single obvious parameter, a score of 3 is adequate.

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 it provides the over-time history ('the radar's evolution') of domain verification observations, and details exactly what data is recorded in the change-log. This distinguishes it from sibling tools like status_history or snapshot_diff by focusing on the append-only history of domain machinery tuples.

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 implies this tool is for retrieving historical change-log data for a domain ('Every domain verify appends...'), but it does not explicitly state when to use this tool versus alternatives or provide exclusions. It explains the data source and semantics, but not the decision context for choosing it over other lookup tools.

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