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

With no annotations, the description carries full transparency burden. It discloses the tool is guidance-only, explains VAT applicability, and specifies that professional fees are market ranges not firm fees. No destructive behavior is expected, and no authorization needs are mentioned, but the description is sufficiently transparent for a non-mutating calculator.

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?

The description is a single paragraph of moderate length, front-loaded with the main purpose. Each sentence adds value, though some detail (e.g., parenthetical about VAT) could be more concisely placed. Nevertheless, it is efficient.

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, and the description does not detail what the tool returns (e.g., a breakdown of costs). For a simple estimator, this may be acceptable, but more completeness would be helpful. The description covers inputs adequately but lacks return format.

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 baseline is 3. The description adds meaningful context beyond schema: it explains the fee threshold (£5,000) and that professional fees are typical market ranges (not firm-specific) and that VAT may apply. This enriches parameter understanding.

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?

The description explicitly states the tool estimates probate costs in England & Wales, listing specific components (HMCTS fee, sealed-copy costs, professional fee ranges). It clearly distinguishes itself from siblings like calculate_iht by focus on probate costs.

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 provides a caveat ('Guidance, not advice') but does not explicitly state when to use this tool versus alternatives among the 16 siblings. Usage is implied by the tool's purpose, but no exclusions or comparisons are given.

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