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

Annotations already declare the safety profile (readOnlyHint=false, destructiveHint=false, idempotentHint=true, openWorldHint=true), so the description's added value is limited to disclosing what the tool returns (page + PDF with maps, prices, hotel picks). It never states that a persistent shareable artifact is created, nor any auth/quota constraints, which matters for a non-read-only tool.

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 tightly packed sentences with the purpose front-loaded and the enumeration of outputs second; no filler. The trailing scope sentence is slightly redundant with the opening clause 'multi-stop ... itinerary,' costing it the top score.

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?

With no output schema, the description carries the return-value burden well by enumerating the itinerary artifacts. Combined with the closed destination enum in the schema and the Thailand-only scope stated in the text, an agent has enough to invoke this correctly for an aggregating, multi-stop planning tool.

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 67%, and the description only echoes what the schema already says about destinations ('stops in travel order'). It adds nothing about the party-size, date, or language parameters, and does not surface the closed Thailand destination list that constrains valid input.

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 names a specific verb and resource ('Build a multi-stop Thailand itinerary') and enumerates the concrete deliverables (shareable page, PDF, day-by-day plan, map, transport prices, hotels, tours). This is unmistakably distinct from the search_*/book_* siblings, though it never names an alternative explicitly, so it falls just short of the top band.

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?

'Use it for any trip of several days or several places' gives a clear condition for selecting this tool over the per-item search/book siblings. There is no explicit when-not guidance and no named alternative to route to, which keeps it out of the 5 band.

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