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

Annotations already indicate idempotentHint=true, destructiveHint=false, and readOnlyHint=false. The description adds that it 'creates durable diagnostic progress' and 'returns one adaptive question at a time', which are behavioral traits beyond the annotations. No contradiction exists.

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 sentences, front-loaded with the core purpose, and each sentence adds value. The description is concise without unnecessary detail.

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 description covers the main behavior and the key unitId scoping. It does not explain the required subjectSlug or the courseVariant parameter, though an output schema exists to describe return values. Given 5 parameters and moderate complexity, it is adequate but has gaps.

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 only 40% (intent and requestId have descriptions). The description explains unitId behavior but does not clarify subjectSlug or courseVariant. With low coverage, the description should compensate more, but it only partially does.

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 the verb 'Starts' and the resource 'adaptive diagnostic', and it mentions the scoping by unitId. It is distinct from siblings in that it is the 'canonical' starter, but it does not explicitly name an alternative. This is clear enough for an agent to identify the tool's purpose.

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 provides explicit guidance on when to include a unitId versus omitting it, which is the key usage decision. However, it does not contrast with alternative tools or state when not to use it, so it is not fully explicit but gives useful context.

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