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

Annotations already cover the safety profile (readOnlyHint, idempotentHint, destructiveHint=false, closed-world), so the bar is lower. The description still adds real value by disclosing a behavioral limit — 'no breach-database lookup' — and enumerating the return shape, which the annotations do not convey.

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 short sentences, front-loaded with purpose, then the safety constraint, then the return contract. Every clause carries information; nothing is redundant padding.

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?

There is no output schema, so the description compensates by listing the returned fields ({ok, score, entropyBits, length, sets, reasons, suggestions}) and explicitly scoping out breach lookup. For a one-parameter read-only tool this is complete enough to call 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?

Schema description coverage is 100% and the single 'password' parameter is already documented in the schema as a fictitious test password. The description's dummy-password warning reinforces but does not extend the schema, so the baseline of 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 ('Evaluate password strength') plus the method ('local heuristics'), which cleanly separates it from the sibling generator (generate-password) and the other validators (is-card-safe, is-email-safe). An agent can identify the operation without opening the schema.

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 an explicit use condition: 'Use only with dummy passwords when testing password policies.' That is a genuine when-to-use constraint, though it names no alternative tool or exclusion beyond the dummy-password rule (e.g., it does not point to generate-password for creating test inputs).

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