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

Annotations cover the safety profile (readOnly, non-destructive, idempotent), and the description adds real value beyond them: the output surfaces as MCP text visible to the client, and seeded output is predictable while unseeded uses cryptographic randomness. That explains the idempotency claim rather than contradicting it.

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?

Purpose is front-loaded and the sentences are short, but "Never use seeded outputs as secrets" and "Never use seeded passwords as actual production credentials" are near-duplicate warnings, and the final client-visibility caution is a fourth consecutive caveat trailing the substance.

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 3-optional-parameter generator with no output schema, the description covers what it returns (MCP text), the randomness model, and the testing-only constraint. It is close to sufficient; only defaults and result length/format phrasing are absent.

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%, including the seed determinism warning, so the schema already carries parameter meaning. The description echoes the seed caveat but adds no syntax, default, or format details the schema lacks – 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?

"Generate a random password with WebCrypto" gives a specific verb and resource, and the fixtures/testing framing differentiates it from generate-token or generate-hash. However it never names a sibling or explicitly contrasts scope with them, so the differentiation is inferred rather than stated.

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?

"Use to populate synthetic account fixtures" states a clear context, and the two warnings about seeded output mark a when-not-to-use boundary. No alternative tool is named as a substitute, so it stops short of full routing guidance.

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