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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false Brief: description adds valuable behavioral context: stops are checked open on the given date, only best-scored venues are selected, and editorial itinerary titles are included. It does not contradict the annotations, and while it doesn't discuss rate limits or error behavior, the safety profile is well covered by annotations.

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 dense sentences carry all relevant information without filler. The first sentence front-loads the core operation and read-only nature, then lists filters and output. The second sentence adds an actionable alternative. 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?

Given there is no output schema, the description adequately conveys the shape of returned data (venues per slot, bookable experience, editorial itinerary titles) and the key validation rule (venues open on the date). Minor gaps like explicit slot definitions or exact return structure prevent a 5, but the tool is callable from this description alone.

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 all six parameters are already documented. The description adds marginal value by naming which parameters act as filters ('neighbourhood, dietary need and price tier') and by tying `date` to the open-check behavior, but it does not introduce new semantic details beyond 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?

The description identifies a specific verb and resource: 'Compose a wine day for one city', and details the output: one best-scored open venue per slot, filtered by neighbourhood, dietary need and price tier, plus a bookable experience. It also clearly separates itself from the sibling `itineraries` by saying editorial itineraries are 'the better plan' when one exists.

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 explicitly tells the agent when to prefer an alternative: 'which are the better plan when one exists (fetch them with `itineraries`)'. It also states the tool is read-only alerts to side-effect-free use operationally. This gives concrete routing guidance beyond a generic 'use this to plan'.

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