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

Annotations already declare readOnly/idempotent/non-destructive and a closed-world search. The description adds behavior beyond that: results are ranked with 'servers seen working on fxapis first,' and absence from results is explicitly non-blocking. Those are non-obvious traits not captured in the annotations.

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 short clauses plus an example, with the resource and matching rule front-loaded. The example is mildly redundant with the schema's own example but is cheap and useful; no filler sentences.

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?

An output schema exists, so return shapes need not be described. Combined with full schema coverage, the description supplies the remaining essentials: what is matched, ordering, and the caveat about unlisted servers. Only result limits/pagination behavior are left unstated, which is a minor gap for a search tool.

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 parameters are fully documented in the schema, including the query format and the concise/detailed response_format enum. The inline example restates what the schema already says and adds no new syntax or constraint information.

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 ('MT5 broker servers matching a broker or server name') and clarifies the matching semantics. No sibling tool overlaps with this lookup function, so differentiation is not needed, but the phrasing is precise rather than a restatement of the title.

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 gives clear context for use — matching by broker or server name prefix — and adds a valuable caveat that 'a server not listed can still be used,' which prevents an agent from wrongly concluding a broker is unsupported. It does not, however, name a workflow or alternative to compare against.

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