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

Beyond the readOnly/non-destructive annotations, it discloses substantive behavior: evidence only from published rates and booking aggregates backed by ≥3 distinct organizations, coverage 'none' with null range when evidence is missing, and that prices are never model-invented. These are constraints the agent could not infer from the schema or annotations.

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 purpose and evidence policy are front-loaded, and the sibling contrast sits at the end where it is most useful. It is dense and somewhat repetitive (the market→region→country walk is stated in both description and schema), but nearly every clause carries information.

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 9-parameter, evidence-driven lookup with an output schema, the description covers the input contract, the fallback resolution behavior, and the guarantee about where numbers come from. Nothing an agent needs to call it correctly or interpret it is missing.

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%, so the schema already documents every parameter, including the 'echoed back, does not filter yet' notes on event_type/guest_count/duration_hours. The description restates those limits and adds the region/country fallback semantics, but adds little syntax-level meaning beyond the schema; baseline 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?

States a specific verb and resource (returns evidence-backed market price ranges for named live-event service categories) and enumerates the covered categories. It explicitly distinguishes itself from sibling quote_event, so an agent can route between the two without opening either 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?

Gives clear situational context: this is the real-evidence lookup, contrasted against quote_event's synthetic catalog, and it explains the market→region→country lookup walk. There is no explicit when-not guidance beyond that one sibling contrast, so it falls short of a full 5.

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