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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive, closed-world). The description adds real value beyond them by describing the informational nature of the response (service coverage, fare differences, post-quote process, contact path) and reinforcing "Submits nothing" so the agent knows no state change occurs.

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?

A single sentence, front-loaded with the core purpose and ending on the disambiguating "Submits nothing." Every clause conveys distinct content, 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?

An output schema exists, so return values need not be explained, and the one optional parameter is fully documented in the schema. For a low-complexity informational tool, the description supplies 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?

Schema coverage is 100% with the enum documented as "Which market to describe. Defaults to en." The description only echoes "for one market" and adds no syntax, fallback, or behavior detail beyond the schema, so the baseline of 3 applies.

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?

Names a specific verb (Describes) and resource (easygroupflights) and enumerates the exact content covered: who it serves, fare differences, post-quote flow, and human contact. This clearly separates it from the action-oriented siblings (search, prepare, request, send), which an agent can see without opening any schema.

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 clause "Submits nothing" tells the agent this is an informational read, not a transaction, which implicitly routes transactional needs to the prepare/request/send siblings. However, no sibling is named and there is no explicit statement of when to prefer this over egf_get_offer or egf_search_flights.

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