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

With no annotations, the description carries the full burden. It usefully discloses authentication ('Requires a valid Druk Asia API key, sent automatically via the x-api-key header') and the read-only nature is implied by 'Retrieves', but it says nothing about pagination, result volume, rate limits, behavior for years with no festivals, or error responses.

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?

Two sentences, both earning their place: the first front-loads the resource, domain, and filter; the second covers the auth prerequisite. No filler or redundant restatement of the title.

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 simple two-parameter read tool with 100% schema coverage, the definition covers purpose, scope, filter, and auth. The only real gap is that no output schema exists and the description does not indicate the shape of returned festival records (fields, ordering, count).

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 both the 'year' range/format and the 'ispopular' enum are already documented in the schema. The description restates that year is required and ispopular is an optional filter but adds no syntax, defaulting, or edge-case meaning beyond the structured fields.

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 verb and resource ('Retrieves upcoming festivals'), plus the domain and scope ('in Bhutan for a specified year') and the optional narrowing ('popular festivals'). It is clearly distinct from siblings like list_destinations or list_itineraries, though it does not explicitly state the distinction.

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 only implied: an agent can infer 'call this when you need festival dates for a year' from the phrase 'upcoming festivals ... for a specified year'. There is no explicit when-to-use/when-not guidance and no mention of alternatives such as itinerary or destination tools an agent might confuse this with.

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