list_films

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

With no annotations provided, the description carries the full burden. It discloses that the tool is 'cheap' (cost/performance), that it returns 'without showtimes' (content limitation), and that 'cinema ids that belong to other chains are dropped' (filtering behavior). These go beyond the schema and give the agent a realistic expectation of the tool's behavior.

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 two sentences with no filler. The first sentence front-loads the core purpose and limitation, the second provides workflow and parameter context. Every sentence earns its place, and the structure is easy to scan.

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?

There is no output schema, so the description must convey what the tool returns. It states it provides an 'overview of the films playing' and that it's used to 'discover which films are worth querying,' implying it returns film identifiers. While it doesn't enumerate exact fields or pagination, it's sufficient for a simple listing tool in the given workflow. Minor gap: no explicit mention of return format, but not critical.

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 the baseline is 3. The description adds extra semantic value for the chain parameter by explaining its use case ('loyalty promotions', 'compare apples to apples') and reiterating the filtering behavior. This goes beyond the schema's description and helps the agent choose the right value.

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 clearly states a specific verb ('list') and resource ('films'), and adds critical scope: 'playing in the given cinemas on the given date, without showtimes.' It also differentiates from siblings by explicitly positioning it between list_cinemas and get_showtimes, so an agent can immediately tell what this tool does and how it fits.

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 description gives explicit workflow guidance: 'Use this after list_cinemas to discover which films are worth querying with get_showtimes.' It also explains the chain parameter's purpose ('for loyalty promotions') and the filtering behavior, leaving no ambiguity about when and how to invoke the tool.

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