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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false and openWorldHint=false, so the safety profile is covered. The description adds genuinely useful caveats that estimates (travel, runtime, trailer) are non-binding and that no tickets are booked, but it says nothing about how the optional filters constrain results or whether an empty result is possible.

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 sentences, front-loaded with the operation and scope, followed by the caveats. No redundant restatement of the tool name and no filler.

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 values need not be described. However, for a six-parameter tool where four optional filters are undocumented in both schema and description, the definition leaves an agent unable to use the narrowing parameters confidently.

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% across six parameters, so the description carries the full burden and largely fails. It names only the required theatre and date; movie, format, minGap and maxGap receive no explanation, and the 0-240 integer range for the gap parameters is never identified as minutes or otherwise defined.

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: pairs of movies at the same theatre for a single theatre and date, computed by a 'pairing engine'. This distinguishes it from search_showtimes and get_best_showings, which return individual showings, though the description never names those siblings 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?

The scope ('one theatre and date') implicitly tells the agent this is a per-theatre query, but there is no explicit when-to-use guidance or routing versus search_showtimes, get_best_showings, or find_theatres. An agent must infer that this is the double-feature-specific path.

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