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

Annotations already declare readOnlyHint=false and idempotentHint=true. The description adds the meaningful constraint that only PREPARING draft use cases can be updatedational context by stating that use cases group related tasks. This goes beyond the annotations without contradicting them.

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 two sentences with no filler. The core action and constraints are front-loaded, and the extra context about use cases grouping related tasks is brief and relevant.

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 low-complexity update tool with annotations covering safety and idempotence, the description covers the essential constraint (PREPARING drafts), the updatable fields, and the resource type. It does not describe return values, but no output schema exists and updates typically do not require extensive return documentation. Overall, it is nearly complete for an agent to call it correctly.

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%, so the description must compensate. It clarifies that title and description are the updatable fields and that useCaseId identifies the target use case, but it does not describe the ID format, whether at least one field must be provided, or whether omitted fields remain unchanged. Some meaning is added, but not full compensation.

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 verb ('Update'), a specific resource ('use case in a draft UT'), and the exact fields that can be changed ('title, description'). It also distinguishes itself from siblings like add_use_case and delete_use_case by focusing on modification of existing use cases.

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 gives an explicit applicable condition: 'Only works on use cases of PREPARING drafts.' This tells the agent when the tool is valid and indirectly when it is not. It does not explicitly name alternative tools for non-PREPARING drafts, but the condition is clear enough.

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