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

Annotations already declare readOnlyHint=true and openWorldHint=false, so the safety profile is covered. The description adds that answers are prepackaged content domains and that FAQ keyword matching is optional, which is useful, but it omits whether answers are static versus searched and how unmatched FAQ keywords behave.

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 front-loaded sentence that opens with the purpose then lists topics in enum order, with the optional-parameter note placed last. The mid-sentence enumeration is long but every item earns its place by mapping to a topic value.

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 two-parameter read-only content router with no output schema and covered annotations, the description is nearly sufficient. The remaining gap is behavior on unmatched or ambiguous topic/question input, which is minor for this tool's complexity.

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 50%: the question parameter is already documented in the schema, and the topic enum values are largely self-describing, so the description's prose list mostly restates them. The one genuine addition is clarifying that cost_to_build explains why no calculator exists and how to get a real number, plus 'Optionally' reinforcing that question is not required. Marginal value over the schema.

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 and audience ('Answers a buyer's questions before purchase') and enumerates the exact content domains it covers, which maps one-to-one to the topic enum. An agent can distinguish it from get_plan, search_plans, and list_features 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 'before purchase' framing and the topic list give clear context for when this tool applies, and the enumeration implies which question types route here. It stops short of naming alternatives or exclusions, e.g. telling the agent to use get_plan for a specific plan's details rather than asking this tool.

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