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

Annotations already declare readOnly, idempotent, non-destructive and closed-world, so the safety profile is covered. The description adds genuinely new behavioral context: the scope is fixed to the current week (no date argument), and the payload includes article text, listed events with dates and pages, and the article page itself.

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?

One dense sentence that front-loads the core identity (weekly picks article) before the routes feature and the return contents. Slightly packed with appositive clauses, but no sentence is wasted.

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 correctly carries the burden of describing return values, which it does at field level. The only meaningful gap for a zero-required-param read tool is behavior when no article exists for the week, which goes unstated.

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?

There is a single optional parameter and schema coverage is 100%, with an explicit note that source data is Korean and non-Korean values are machine translations, plus a default of 'en'. The description contributes nothing about lang, so the baseline 3 for a fully documented single-parameter schema 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 names a specific resource (kfestivals' latest weekly article) plus its companion feature ('festival trail' 2-day routes linking 2–4 nearby festivals) and enumerates what comes back. An agent can distinguish it from search_festivals/get_festival as editorial content rather than a query endpoint, though it never names those siblings 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?

Usage is implied by 'this week' — the tool is for current-week recommendations — but there is no explicit when-to-use versus search_festivals or get_festival, and no stated exclusion such as 'no date parameter; use search_festivals for other weeks or arbitrary date ranges.'

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