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

Annotations already declare readOnlyHint=true and destructiveHint=false, so the safety profile is covered. The description adds valuable behavioral context beyond annotations: all media comes through Sedna's CdnManager, missing CDN media is returned as an empty field and never replaced by a legacy DB URL, and the tool does not return date-specific prices/extras/availability. This gives the agent important expectations about data provenance and absence semantics.

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 well-structured and front-loaded with the core purpose, then flows into usage context, media handling, and exclusions. It is slightly long but every sentence earns its place by conveying critical routing and behavioral information. The only minor inefficiency is the somewhat dense enumeration of media fields, which is necessary for correct display.

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 read-only tool with 3 parameters, 100% schema coverage, and no output schema, the description is quite complete. It covers what the tool returns, how to invoke it after search_boats, how to handle missing media, and what it does not return. The only gap is that it doesn't describe the exact structure of the response beyond field names, but since there is no output schema, the field enumeration partially compensates. It could also mention pagination or error behavior, but these are minor for this tool's scope.

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 schema already documents all three parameters. The description adds meaningful context beyond the schema: id_boat must be copied exactly from search_boats (reinforcing the schema's 'Never guess it'), sheet_type=crewed is tied to crew and itinerary data, and the media fields returned are enumerated. This exceeds the baseline 3 by adding usage-oriented parameter semantics.

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 ('Return') and resource ('yacht details and CDN-backed public URLs for yacht media'), and explicitly distinguishes this tool from siblings by naming search_boats and booking_detail. It also enumerates the exact media fields returned, making the tool's purpose unmistakable.

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 says this is the primary tool to call after search_boats whenever the customer asks for photos, gallery, plans, videos, documents, layout, capacity, dimensions, equipment, description, crew, or itinerary. It also names booking_detail as the alternative for date-specific prices, extras, or availability, and instructs to copy id_boat exactly from search_boats. This is explicit when-to-use and when-not-to-use guidance.

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