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

With no annotations, the description carries the full burden. It usefully discloses that it is an affiliate search layer, does not book directly, and returns ranked options with option_id for affiliate deep-links. It omits authentication requirements, rate limits, and pagination behavior.

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?

Three tightly written sentences with no waste. Purpose is front-loaded, followed by return format and key behavioral disclaimer, making it easy to scan and understand.

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 complex tool with 8 parameters, no output schema, and no annotations, the description covers the essential purpose and return type. It could better explain the importance of date parameters or session reuse, but the schema handles most parameter details.

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 88%, so the schema already documents parameters thoroughly. The description adds no parameter-level meaning beyond what is in the schema, which is acceptable given the high coverage.

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 'Metasearches' and resource 'car rentals, campervans, and local vehicle fleets' with clear geographic scope (Europe, North America, alpine corridors). Explicitly distinguishes from booking siblings with 'Does not book directly — acts as affiliate search layer.'

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?

Provides a clear context and an exclusion ('Does not book directly'), which tells the agent this is for search, not booking. However, it does not name a specific alternative tool or state when to choose this over other search tools (e.g., geo360_search_flights).

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