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

Adds meaningful context beyond the annotations: Node's CSPRNG source, fresh generation per call, no storage or logging, free pricing, and that errors return isError without being charged. The annotations only declare readOnly/openWorld/idempotent/destructive=false, so the security and billing disclosures are genuinely additive. It stops short of describing output format or pagination, but with an output schema present that is acceptable.

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?

Two dense sentences, capability list front-loaded, then guarantees and pricing/error notes. No filler and nothing redundant with the title.

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 multi-mode generator with 7 optional params and an output schema, the description supplies the security, freshness, no-logging, pricing, and error-handling context an agent needs to decide to call it. Only minor gaps remain (e.g. return shape for count>1), which the output schema likely covers.

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 every parameter (min, max, kind, count, items, length, symbols) is already documented in the schema with defaults and ranges. The description names the kinds but adds no syntax, format, or constraint detail beyond the schema, so baseline 3 applies.

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 with an explicit enumeration of the nine output kinds (UUID v4/v7, passwords, tokens, ints, dice, coin, shuffle/pick), which lets an agent confirm capability without opening the schema. No sibling tool in the list covers secure randomness, so differentiation is inherent and stated via 'cryptographically secure'.

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 covers what it generates and mentions 'free' and error behavior, but never states when to prefer this tool over an alternative (e.g. hash_encode for deterministic IDs) or any prerequisites. Usage is implied by the kind list rather than guided.

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