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

Annotations already indicate readOnlyHint=false and destructiveHint=false, so the description doesn't need to restate safety. The description adds valuable behavioral context: the reference prefix is used for numbering checks (SUP-01, SUP-02) and the uniqueness constraint across sections in an app. This goes beyond the schema and annotations.

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, front-loads the core purpose, and every sentence adds value. The reference-prefix explanation is concise and directly relevant to correct usage.

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 creation tool with no output schema, the description covers the key behavioral aspects: what a section is, how ref works, and the uniqueness constraint. It doesn't mention error cases or whether the operation is reversible, but annotations already cover the safety profile and the schema covers parameters.

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 100%, so the schema already documents all three parameters. The description adds context about the 'ref' parameter's role in check numbering and its derivation from title if omitted, which is useful. However, it doesn't add much beyond what the schema already provides for 'app' and 'title'.

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 ('Add') and resource ('a section to an app'), and clarifies what a section is ('a module or feature area'). It also distinguishes the tool from siblings by explaining the reference prefix behavior, which is unique to this tool.

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 when to use this tool: when creating a section within an app, and it clarifies the uniqueness constraint ('No two sections in an app may share one'). It doesn't explicitly name alternatives or exclusions, but the sibling list and the specific resource make the usage context clear.

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