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

The description discloses that generation is local, uses a cryptographic random source, and returns a JSON array of strings. This goes beyond the readOnlyHint annotation by specifying execution environment and output format, giving an agent confidence about side effects and network usage. No contradiction with 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 four sentences, front-loaded with the core purpose, then logically expands on versions, execution, and output. Every sentence contributes new information with no filler or repetition of the title or schema.

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 two-parameter tool with no output schema, the description covers the essential context: what it does, version behavior, execution environment, and return format. The schema covers parameters, and the annotations cover safety. An agent has everything needed to call this tool 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?

The schema already documents both parameters fully (count range/default, version constraints/default). The description adds value by explaining the semantic difference between version 4 (fully random) and version 7 (timestamp-based, sortable), which is not captured in the schema's brief descriptions. This enriches parameter understanding without redundancy.

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 opens with a clear verb+resource ('Generate UUIDs') and immediately distinguishes the two versions (v4 random, v7 timestamped). This is specific and unambiguous, and while it doesn't name a sibling, none of the siblings are UUID-related, so the purpose is fully clear on its own.

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 provides implicit usage guidance by noting v7 'suits database keys', which helps an agent choose between versions. It also notes the tool runs locally, which is relevant for privacy-sensitive contexts. However, it does not explicitly state when to use this tool vs. an alternative (though no direct alternative exists among siblings), and it doesn't mention any constraints like the count limit (though the schema does).

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