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

Annotations already declare readOnly/idempotent/non-destructive, so the bar is lower. The description adds real context beyond that: server-side date math resolves the Fri/Sat/Sun dates, results are grouped by day, and it is 'Schedule data, not live seat inventory' – a useful boundary against availability tools.

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?

Three compact sentences that front-load the trigger condition, then the mechanism, then the data boundary. No filler or restatement of the 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?

An output schema exists, so return structure need not be described, and annotations carry the safety profile. The description supplies trigger, scope, grouping, and data-type boundary, leaving little an agent needs to call it 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%, so the baseline is 3. The description goes slightly beyond by explaining that weekend date resolution is server-side, adding meaning to the 'weekend' enum and city parameters that the schema alone does not convey.

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 and resource with scope: 'returns theatre shows in the city with scheduled performances on those days, grouped by day.' The weekend-only, per-day framing implicitly separates it from whats_on_tonight and get_whats_on_this_week, though no sibling is named explicitly.

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?

Opens with an explicit trigger: 'Use this when the user asks what theatre is on this weekend or next.' Clear context, but no when-not guidance (e.g., redirecting seat-availability questions to check_availability beyond the closing caveat).

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