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

Annotations already establish readOnly/non-destructive, but the description adds non-obvious behavior: results are limited to 31 days and 20 rows, and approval-mode times are preferences rather than holds. This materially changes how an agent should interpret results.

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 where each clause delivers a distinct constraint or caveat. There is no filler, repetition, or redundant restating of the tool name.

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 output schema and annotations present, the description covers the operational constraints that affect invocation and interpretation: range cap, row cap, and approval-mode semantics. Nothing essential is missing for correct tool use.

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 low (25%), but the description compensates: it identifies service_id as an exact service, provider_id as optional, and constrains date_range to YYYY-MM-DD up to 31 days. Tenant semantics are already well-documented in the schema, so the gap is acceptable.

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 states a specific verb ('Returns'), a concrete resource ('current open times'), and the selection scope ('one exact service and optional provider') with range limits. This makes it distinct from sibling service-discovery tools like find_available_services, which work across services.

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?

It clearly implies the call context: the caller must already know the exact service (service_id is required) and a date range, with provider optional. It doesn't explicitly name alternatives or exclusions, so it stops short of a full when-to-use/when-not-to-use guide.

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