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

Annotations already cover safety (readOnly, idempotent, non-destructive, closed-world), so the description wisely spends its words elsewhere: data language (Korean), the returned fields, and the requirement to cite the festivaltimes.net URL. It does not mention pagination behaviour beyond `limit`, but the citation instruction is a meaningful behavioral addition.

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?

Four tight sentences that front-load the scope, then the date semantics, then the return payload, then the citation rule. No sentence is filler and nothing is buried.

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?

With no output schema, the description compensates by enumerating the returned fields (name, dates, region, venue, summary, URL). Combined with the zero-required-parameter default range and the citation requirement, an agent has everything needed to call and use the result 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%, so parameter syntax is already handled. The description still adds value by disclosing the default window (today to +30 days) and the overlap semantics ('running at any point between `from` and `to`'), which the schema does not state.

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 ('Search festivals in South Korea') plus the data source (Festival Times). It implies differentiation from festivals_this_weekend by specifying an arbitrary from/to window, but never names any sibling tool explicitly.

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 default date range (today to 30 days later) gives useful context for when the tool applies out of the box. However, there is no explicit guidance on when to prefer this over festivals_this_weekend or when to use get_festival for a single festival, so routing is only implied.

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