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

Annotations already cover safety (readOnlyHint, idempotentHint, openWorldHint=false, destructiveHint=false), so the bar is lower. The description still adds genuine context by previewing the payload an agent will receive, including derived fields like coordinates and the kfestivals page link. It omits error behavior for an unknown id.

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 sentence, front-loaded with the identity of the tool, with the id-source hint adjacent to the id mention. Every clause is a field or a routing fact; nothing is padding.

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 carries the return-value burden and discharges it by listing the returned fields. Given a simple two-parameter read tool, that is nearly complete; only failure modes for an invalid or expired id are unspecified.

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 the baseline is 3 and the schema already documents both id and lang. The description adds value beyond the schema by stating the provenance of the id value, which the id parameter's schema text does not.

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 with explicit scope: 'Full details of one festival by id.' The parenthetical naming search_festivals and get_festival_picks as id sources separates it from the sibling search tools, and the field enumeration ('dates, venue and address with coordinates...') makes the depth distinction concrete.

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?

Tells the agent exactly where to obtain the required id (search_festivals or get_festival_picks), which is the practical prerequisite for calling this tool. It gives no explicit when-not case and does not reference search_concerts, so the routing picture is slightly incomplete.

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