List the diagram kinds

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

Annotations already declare readOnlyHint and idempotentHint, so safety is covered; the description adds genuine behavioral context by warning that several kinds 'are not box-and-arrow diagrams and are easy to miss,' steering the agent away from a wrong assumption. It does not describe the return format, but the annotations and the 'vocabulary' framing carry most of that burden.

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?

Three short sentences, front-loaded with what the tool is, then the arity, then the usage directive. Every sentence earns its place with no filler.

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 zero-parameter enumeration tool with no output schema, the description tells the agent what the tool returns ('every value `kind` may take and what each one is for') and when to consult it. Nothing needed to call it correctly is missing.

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?

There are no parameters, so the baseline is 4. The description correctly states 'Takes no arguments,' matching the empty schema, adding no confusion.

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 states a specific resource — 'the vocabulary: every value `kind` may take and what each one is for' — which is unambiguous and distinct from the sibling tools validate and render. It lacks an explicit verb of its own (the title supplies 'List'), but the intent is clear without opening the schema.

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?

It gives a clear directive: 'Read this before choosing a kind,' which tells the agent exactly when to call it. No when-not condition or named alternative is offered, but for a zero-argument vocabulary lookup the trigger is fully sufficient.

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