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

The annotations already declare readOnlyHint=true and openWorldHint=false, telling the agent this is a safe, closed-domain read. The description's only added behavioral content is that the return is an expansion plus a definition. It says nothing about what happens for an unrecognised term or whether aliases/synonyms are matched, which would matter when a lookup misses.

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, zero preamble, with the purpose stated first and the examples used as the qualifier. Nothing could be removed without losing specificity.

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 one-parameter, read-only glossary tool with full schema coverage and no output schema, the description supplies enough to call it correctly. The remaining gap is behavioural (fallback on unknown terms), which is minor at this complexity.

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 single 'term' parameter is already documented in the schema with its own examples, including a multi-word phrase ("deemed dividend distribution"). The description's example list is largely redundant with the schema, so this is the expected baseline rather than added value.

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?

Specific verb pair ("Expand and define") plus a bounded resource ("acronym or term used in Cyprus corporate and tax practice"), reinforced with five concrete examples. It stops short of distinguishing itself from the adjacent cyprus_fact_lookup sibling, so an agent must infer that fact retrieval belongs elsewhere.

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?

The description establishes a clear triggering context: the agent has an acronym or practice term it cannot resolve. The examples (SDC, VIES, ASP, NID, CFC) make the intended input class concrete. No explicit exclusion against the fact-lookup or VAT-registration siblings is given.

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