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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint=false, so safety is covered; the description adds genuinely new behavior — the exact {"error": "not_found"} response for missing or inactive ids and the downstream citation rule. The only gap is the shape of the successful return value, which no output schema documents either.

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, zero waste, with the primary action and its provenance front-loaded before the failure-mode rule. Nothing is padded or restated.

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 two-parameter read tool with full annotation coverage and full schema coverage, the description covers the essential call path and the failure case. It omits the shape of a successful response, which matters slightly since there is no output schema.

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% and both parameters (id and lang enum) are documented in the schema, so the schema does the heavy lifting. The description's note that the id comes from search_exhibitions largely restates the schema's own wording, adding no syntax or format detail.

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 ('Fetch one exhibition by id') with a scope qualifier that separates it from the list-oriented sibling search_exhibitions. An agent can distinguish it from list_cities, search_venues, and search_exhibitions immediately.

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?

Explicitly ties the required id to search_exhibitions results, which tells the agent the correct call order. It also gives an explicit when-not rule: if the response is not_found, 'do not cite such an exhibition.' It stops short of naming alternatives for other retrieval cases, so it is clear context rather than a full when/when-not matrix.

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