Expand one itinerary

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

No annotations are provided, so the description carries the burden. It discloses the read-only nature implicitly by focusing on 'show' details, specifies the output granularity (per-segment) and exact data points, and notes session reuse and performance ('fast'). Missing are error conditions, but for a detail-retrieval tool this is adequate.

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 compact sentences: the first states the purpose and output fields, the second adds behavioral context about session reuse and speed. Every word earns its place with no redundancy or filler.

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 simple 2-parameter tool with no output schema, the description covers the essential context: what it does, what it returns, when it is used, and a performance note. It implicitly states the prerequisite (a prior search) and the field list serves as the return-value specification. No critical gaps for this complexity level.

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%, with both parameters (searchId, rank) already described in the schema. The description adds context that the itinerary is from a previous search, but no new parameter-specific semantics beyond the schema's explicit examples and definitions. Baseline 3 is appropriate.

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 verb ('Show') and resource ('per-segment detail for one itinerary from a previous search') with specific fields (operating flight numbers, booking class, fare basis codes, aircraft type). This differentiates it from siblings like search_flights, which perform the initial search, and lookup_airport, which handles airport lookups.

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 indicates the tool is for expanding a previously returned itinerary ('from a previous search', 'Reuses the earlier search session'), providing clear context for when to use it. It does not explicitly name an alternative or state when not to use it, but the session-reuse detail effectively excludes standalone use.

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