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

Annotations already declare readOnly, idempotent, openWorld, and non-destructive, so the safety profile is covered. The description still adds real behavioral value: the free tier returns only the latest three records, and the archive and full fields are gated behind PRO access, which materially changes what an agent receives.

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, front-loaded sentences with no filler. It is efficient, though extremely sparse for a tool whose resource and parameter are both unexplained.

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 no output schema, the description does partially cover return semantics (latest three / full fields for PRO). But it leaves the required feed_id and the nature of a 'register' vs a 'record' undefined, which are essential for correct invocation.

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 description coverage is 0% and the single parameter feed_id is documented nowhere. The description never mentions feed_id, its format, or where it comes from, so it fails to compensate for the coverage gap.

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 verb 'Read' and the resource 'register' are present, but the description actually describes the free-tier output ('latest three records') rather than what the tool retrieves. It does not distinguish this from the sibling read_record or list_registers, so an agent cannot confidently separate the register read from the record read without opening schemas.

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?

There is no when-to-use guidance and no named alternative among the many siblings (list_registers, read_record, search_record_previews). The 'Scoped PRO access' sentence is an upsell/limitation note, not guidance on when this tool is the right choice.

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