get_daily_costs

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

Annotations already cover read-only/idempotent/non-destructve safety, so the description only needs to add behavioral context. It does so by warning that missing amounts are null, not zero, which prevents a common misinterpretation. This is useful, though it could be more explicit about what triggers the condition.

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 sentence with no padding, so it is concise. However, it is structurally mislead: it front-loads a niche response caveat and omits the primary operation entirely, which makes the terseness a defect rather than a virtue.

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?

Rich annotations and a self-describing input schema cover safety and parameter names, but the description leaves out the tool's core purpose and usage context. The null caveat is valuable but cannot make the overall definition complete for an agent deciding whether to call this tool.

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 0% and the description contains no information about request, area, on_date, or tariff. The input schema's names and enums carry all meaning; the description adds nothing and does not compensate for the low coverage.

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 never states that this tool retrieves daily costs; it only says that with no enabled tariff/expiration in the current catalog, amounts are null and never implicit zero. The action and resource are left entirely to the tool name. This is not a pure tautology, but it is missing a clear purpose statement.

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?

There is no guidance on when to call get_daily_costs rather than check_vehicle_access, query_movein_allownce, or get_active_smog_level. The single sentence is a catalog-state caveat, not a usage condition or alternative-routing rule.

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