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

Annotations already indicate this is a write operation (readOnlyHint false) but not destructive. The description adds behavioral context by noting the group_name must be unique within the sweepstakes and that fetching the token first is required. It doesn't contradict annotations and provides extra value beyond the structured fields.

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 structured with clear sections, but it repeats the opening sentence in the 'When to use' section almost verbatim. The parameter validation section also duplicates the schema. While organized, it could be more concise without losing value.

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 simple create tool with two well-documented parameters and no output schema, the description covers required pre-calls and parameter validation. It provides enough context for an agent to invoke it correctly, though it doesn't mention returned values or error cases, which would be nice but not essential.

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 fully documents both parameters. The description repeats the parameter details without adding new semantic meaning. Baseline of 3 is appropriate since the schema handles the parameter explanations.

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 'Create a new group within a sweepstakes' with a specific verb and resource. It distinguishes from sibling tools like update_group and delete_group by focusing on creation. The additional context about organizing and segmenting participants further clarifies the tool's role.

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 explicitly states when to use the tool and requires a pre-call to fetch_sweepstakes if given a name instead of a token. It provides a clear 'When to use' section, but it doesn't explicitly mention when not to use it or name alternative tools, so it falls short of a 5.

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