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

Annotations already declare readOnly/idempotent/non-destructive, so safety is covered; the description adds real context beyond them by disclosing the source's architectural constraint (no by-id endpoint, hence both params required) and enumerating the returned fields including the PDF URL. No output schema exists, so this return-shape disclosure is genuinely valuable.

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?

Three sentences, each earning its place: identity/keys, the constraint that explains the key choice, and the return shape. The core action is front-loaded with no filler.

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 no output schema, the description covers the source of inputs, the reason both are required, and the returned fields. An agent has everything needed to call it and interpret the result.

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, but the description goes further by explaining the coupling between id and date — both are mandatory because the upstream source only exposes by-day listings — which is meaning the schema alone does not convey.

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 (fetch), resource (single eMarket Storage disclosure), and the exact key (Teleborsa protocollo id + publication date). It explicitly routes to the sibling emarket_search_disclosures as the origin of those keys, so the agent can distinguish this lookup tool from the search tool without opening either schema.

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?

Clearly positions this as the follow-up to emarket_search_disclosures and explains why it is a by-day lookup rather than a by-id one. It gives clear context for use, though it stops short of stating an explicit when-not or naming any other alternative.

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