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

Annotations already establish a safe read-only, idempotent, non-destructive closed-world operation. Beyond that, the description discloses the return size and contents, ten-point score scale, null missing predictions, the qualities_applied field, saved-service usage, and that an authorized account is required and no account identifier is accepted.

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?

Front-loads the trigger and the key alternative before moving into ranking behavior, return shape, and exclusions. It is dense and slightly repetitive around 'saved taste,' but nearly every sentence 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?

Complete for a complex nested personalization tool: it explains authentication, source of preference signal, return format and score handling, rewatch and service behavior, and the chart alternative. The output schema exists, and the description still adds enough 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?

The nested schema documents many fields in detail, but the description adds useful relational meaning: positive and disliked reference titles map to seed and avoid inputs, desired qualities map to mood constraints, watched titles are excluded unless rewatch is requested, and saved streaming services can be used. It still leaves the intent enum values and limit shortlist behavior to the schema.

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: ranks the wider catalogue by saved taste, incorporating liked and disliked references plus desired qualities. It explicitly distinguishes itself from the charts sibling for mood-only starts and clarifies that it uses lasting saved preferences rather than transient mood.

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?

Gives an explicit trigger, 'when the viewer asks to explore their saved taste or the wider library,' and routes open-ended 'Netflix tonight' or 'What should I watch?' requests to get_charts first even when connected. It also states the watched-title exclusion unless rewatch is requested, and the authorization requirement.

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