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

Annotations already cover the safety profile (readOnly, idempotent, openWorld, non-destructive), and the description adds real value beyond them: the free/no-key access model, licensing, and an explicit scope boundary (snapshot only, no officers, shareholders or financials). That scope limitation is exactly the kind of negative information an agent needs.

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 tight sentences with the source, access model, lookup modes, return fields and scope limit front-loaded. Every clause carries information and nothing repeats the tool name.

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 values need not be explained, yet the description still summarizes them helpfully. Combined with the access model and the explicit exclusion of officers/shareholders/financials, an agent has everything needed to decide and call correctly.

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 the schema already documents uen, name and limit precisely, so the baseline is 3. The description restates the name-vs-exact-UEN distinction but adds no new format, syntax or matching semantics (e.g. partial vs exact match behavior) beyond the schema.

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 (Search) plus resource (Singapore's ACRA corporate-entity registry via data.gov.sg) and enumerates what is returned. An agent can immediately distinguish this from sibling registry tools like companies_house_company or sec_edgar_company by jurisdiction and source.

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?

Explains the two access modes (entity name vs exact UEN) and pre-empts misuse by declaring the data is free, keyless and licence-covered. It does not explicitly name alternative registries for other jurisdictions, but the Singapore scoping makes the selection condition clear enough.

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