get_return_flights

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

No annotations are provided, so the description must disclose behavioral traits itself. It does reveal a key dependency: it must be used after an outbound search with a departure_token. The read-only nature is implied by 'get' but not explicitly stated, and there's no mention of return format, pagination, errors, or rate limits. This meets minimum viability but leaves gaps.

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 two sentences: the first states purpose and usage context, the second gives the critical input instruction. Every word earns its place, and it's front-loaded with the primary purpose.

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 tool with no output schema and no annotations, the description covers the essential workflow and key parameter. It clearly explains when to use it and what input to pass. However, it doesn't describe the response shape or any caveats about token validity or matching logic, which would be useful for a flight search tool with this many siblings.

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?

All parameters have schema descriptions (coverage 100%), so the baseline is 3. The description adds value by explicitly highlighting the departure_token and explaining its role in connecting to the outbound search, which goes beyond the schema's per-field descriptions.

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 clearly states the tool's function: 'get matching return flight options for a selected outbound flight.' This specific verb+resource structure distinguishes it from sibling tools like search_flights (general search) and plan_multi_stop_trip (itinerary planning).

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 explicit context: 'After searching one-way outbound flights, use this...' and instructs to 'Pass the departure_token from the outbound search result.' This clearly defines the prerequisite workflow. However, it doesn't explicitly mention alternatives or when not to use it, so it lacks the full explicit exclusions that a 5 would require.

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