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

With no annotations, the description carries the full burden, and it does add useful context: the upstream data source and licence, the fee ($0.25 USDC), and that output includes red flags. It omits key behavior an agent needs, such as what happens when a name matches zero or many companies, whether results are paginated, and whether the fee is charged on 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?

Dense and front-loaded: source, lookup keys, returned fields, examples, and price in a compact space with no filler sentences. The parenthetical provenance clause is slightly cluttered but still earns its place by establishing trust in the data.

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?

There is no output schema, so listing the returned fields is valuable, and the examples cover the two primary lookup modes. But for a 7-parameter tool with zero schema documentation and no annotations, five parameters and the multi-result behavior remain unexplained, leaving real gaps before an agent can call it confidently.

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 0% across 7 parameters, so the description must compensate, and it only explains uen and name (with examples). The other five parameters — q, sg, limit, number, company_number — are left completely undefined, and the agent cannot tell how limit interacts with a name search.

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?

Names a specific verb and resource ('Singapore company lookup from ACRA via data.gov.sg'), the lookup keys (UEN or name), and the returned fields. It also differentiates itself from the many sibling country tools (au_company, uk_company, etc.) by jurisdiction and data source without the agent needing to open any 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?

The description makes clear it is a lookup by UEN or name and gives concrete example inputs for both modes, which is implied when-to-use guidance. However, it never says how to choose between this tool and richer siblings like company_full, company_research, or kyb_report, and it gives no rule for which of the 7 parameters to supply.

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