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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, so the safety profile is known. The description adds value by revealing the return behavior: the JSON-LD entry plus bidirectional neighbors (citations in/out), which is not implied by the annotations. This is extra behavioral context beyond the structured metadata.

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 a single, clearly written sentence that front-loads the action ('Resolve a canon concept by URN') and then concisely describes the return value. Every word earns its place, and there is no wasted text.

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?

The tool is simple (one parameter, no output schema), and the description adequately covers what it returns and what kind of data it works with. It doesn't explain error cases or format details, but for a read-only lookup with annotations already providing safety context, the description is sufficiently complete.

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 provides 100% coverage for the single parameter, including type, required flag, and an example. The description doesn't add new meaning to the parameter itself; it relies on the schema. With full schema coverage, 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 uses the specific verb 'Resolve' and identifies the resource as 'a canon concept by URN,' clearly distinguishing this from sibling tools like canon.by_type and canon.list_types. It also explicitly states what is returned, making the tool's function 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 implies this tool is for looking up a specific canon concept when a URN is available, but it does not explicitly mention when to use alternatives like by_type or list_types. The guidance is clear but indirect, so it earns a 3 rather than a 4.

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