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

Annotations already declare the full safe-read profile (readOnly, idempotent, non-destructive, not open-world), so the description need not restate safety. It adds one genuine behavioral detail (price moves returned oldest first) plus cross-type variance, but the bulk of the text describes return contents that the output schema already documents, so the net behavioral contribution beyond the structured fields is modest.

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?

Usage guidance is front-loaded and the disambiguation is placed last, which is the right ordering. However, the long middle sentence enumerating return fields is heavy and largely duplicates the output schema, costing some conciseness.

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?

For a single-argument detail tool with an output schema, the description covers the trigger, the scope (one watch), the per-type content differences, and the sibling disambiguation. An agent has everything needed to select and 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?

There is a single parameter with 100% schema description coverage, including matching by id or traveler-worded name and the multi-match fallback behavior. The description adds nothing about the 'watch' argument, so the schema does all the work; baseline 3 is correct.

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 states a specific verb+resource (return the full detail for ONE watch) and enumerates the four watch types it covers (tracked flight, bucket list, hotel stay, seat watch). It also names what it is not, distinguishing it from the list_* siblings without requiring the schema to be opened.

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?

It gives an explicit trigger ('Use when the traveler asks about ONE of their watches') and an explicit exclusion ('Not for listing every watch (use the list_ tools)'), routing the agent to the correct alternative. Nothing is left to inference about when this tool is the right pick.

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