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

While annotations already declare readOnly/idempotent/non-destructive, the description adds genuinely useful context beyond them: the WebCrypto implementation, the security warning about deterministic seeds, and the critical fact that no token is registered with any service and the value is only visible to the client.

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 dense sentences, front-loaded with the action and security caveat. Semicolon-chained clauses make it slightly packed, but every sentence carries distinct, useful information.

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?

With no output schema, the description compensates by stating what is returned ('a generated value visible to the MCP client') and that nothing is registered externally—exactly the return/behavior context an agent needs for a three-parameter generator.

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 coverage is 100%, so the baseline is 3, but the description adds semantic weight by framing the seed parameter's safety implications ('never use deterministic seed for real secrets')—meaning that isn't captured in the schema's terse 'reproducible test output only' note.

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?

States a specific verb and resource ('Generate tokens/UUIDs with WebCrypto') and explicitly differentiates from siblings by naming generate-hash for file digests. An agent can distinguish this from generate-password or generate-hash without opening schemas.

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?

Gives explicit when ('temporary development fixtures or unseeded random UUIDs'), when-not ('Do not use seeded output as authentication credentials'), and an alternative ('for file digests use generate-hash'). Routing guidance is complete.

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