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

Goes well beyond the readOnly/idempotent/closed-world annotations by disclosing that no sign-in is needed, that an account is required to actually run a Diagnostic, and that the optional inputs cause no lookup or storage. The auth requirement and the no-side-effect guarantee are exactly the behavioral details annotations cannot express.

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 and the no-sign-in guarantee are front-loaded, and every clause adds a fact an agent would otherwise have to guess. The semicolon-chained single paragraph is dense and could be broken into a coverage list for scannability, which keeps it short of a 5.

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 carries the burden of saying what comes back, and it does so exhaustively (pillars, plan prices, service pages, prefilled link). Combined with the auth and no-side-effect disclosures, an agent has everything needed to decide and 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 coverage is 100% and both fields already say they prefill the start link, so the baseline is 3. The description adds real meaning on top by clarifying the parameters are purely cosmetic ('only fill in that link: nothing is scanned, stored or looked up') and that they should be passed as the person gave them, heading off any assumption that they trigger work.

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?

Opens with a specific verb+resource ('Describes Yellowhead Digital') and then enumerates exactly what is covered: the Diagnostic's ten pillars, duration, Free plan scope, every plan with price and monthly Diagnostics, paid scans and human services with prices, plus a prefilled start link. This makes it trivially distinguishable from sibling tools like get_diagnostic, run_diagnostic, and start_diagnostic.

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?

Explicitly states the question shapes it answers ('what Yellowhead does or costs, whether it checks something, or how to get started, including before any account exists'), and the closing clause 'nothing is scanned, stored or looked up' implicitly steers agents away from using it as a results tool. It stops short of naming the alternative siblings (e.g., use get_diagnostic for actual results), so the exclusion is inferential rather than stated.

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