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

Annotations already declare readOnly, idempotent, non-destructive, and a closed world, so the safety profile is covered. The description adds genuinely non-structured context by defining the semantics of the result: "free-by-default" — available simply means nothing is marked against that date. It does not mention behavior for unknown/ambiguous member ids, but the core interpretive rule is supplied.

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?

Two tight sentences with no filler: the single-member/date scope is front-loaded, the free-by-default rule follows, and the routing hint comes last. Every clause earns its place.

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?

For a two-parameter read-only lookup with full schema coverage and no output schema, the description is nearly complete; the return shape need not be explained. Only minor edge cases (nonexistent member, ambiguous slug) are left unspecified, which is a small residual gap.

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%, so both parameters are already documented and the baseline is 3. The description adds only marginal meaning — that the member may be an artist or a venue and that the id comes from a search/get_profile result — while the schema carries the slug/date format detail.

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 (check), specific resource (ONE named member), and specific scope (free on a specific date), then immediately differentiates itself from the nearest sibling: finding WHO is free belongs to search_available_performers. An agent can pick between them without opening either 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?

Explicitly gives the triggering question ("is X free on the 14th?") and names the alternative tool plus the condition that selects it ("finding WHO is free is search_available_performers"). Both the when-to-use and the when-not-to-use are covered.

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