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

Annotations already cover the safety profile (readOnlyHint, idempotentHint, destructiveHint=false), so the description's added value is in disclosing that it returns one complete guide rather than excerpts and that identical content exists as a resource. It does not describe format, length, or whether guides are chunked, which would have rounded this out.

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?

A single front-loaded sentence with the verb and resource first, followed by the topic inventory and the resource alternative. The topic list makes it long-ish, but every clause carries selection-relevant information; 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?

With an output schema present, return-value explanation is not required, and the description supplies everything needed to pick a topic and invoke correctly. Minor omissions are format and size of the returned guide, which an agent might reasonably want.

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% and the enum carries the five values, so the baseline is 3. The description earns above baseline by explaining what each enum value actually contains (e.g. 'customs-codes' = segments, residuals and historical selections), which the schema's generic parameter description does not provide.

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 states a specific verb and resource ('Read one complete MCP guide') and then enumerates the five selectable topics with a parenthetical summary of each. That is enough to separate it cleanly from every sibling tool, all of which return trade data rather than documentation.

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?

It makes clear this is the documentation-reading tool and names an explicit alternative channel ('The same canonical text is available as `eu-trade://docs/<topic>` resources'), which tells the agent it can bypass the tool call. It stops short of saying when the resource route should be preferred over the tool, so the choice is left partly to inference.

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