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

Annotations already declare readOnlyHint and openWorldHint, so safety is covered. The description adds that the operation returns the full definition and notes, which is useful, but it does not detail return shape, missing-entry behavior, or site-specific quirks.

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?

One dense sentence with no filler. The resource, lookup keys, and input provenance are all front-loaded.

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 two-parameter read-only lookup, the description is largely complete: it names the inputs, identifies the output scope, and points to the search tool for id discovery. Minor gaps remain around exact response contents and error conditions.

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 50%; id is documented with an example, while site relies on its enum. The description adds the important note that ids originate from canon_search, but site semantics are still left almost entirely to the schema enum.

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?

States a specific verb ('get'), a specific resource ('one entry'), and the scope ('full definition and notes'). It also distinguishes itself from canon_search by noting that ids come from search, and the singular 'one entry' separates it from batch or list siblings.

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 phrase 'ids come from canon_search' gives clear context for when this tool is appropriate: after search results have produced a site and id. It doesn't explicitly name alternatives or exclusions, so it isn't a perfect 5.

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