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

Annotations cover the safety profile (readOnly, idempotent, non-destructive), and the description adds real behavioral value beyond them: the removals_visible:false flag, the fact that withdrawals are structurally invisible, and that comparable:false with a reason is returned instead of a misleading zero when the date exceeds published data.

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 dense sentences, front-loaded with the core scope before the caveats, and every clause carries information (order, coverage limits, fallback behavior). Slightly heavy on stacked parentheticals, but nothing is wasted.

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 no output schema, the description appropriately compensates by disclosing the response shape signals (removals_visible:false, comparable:false with reason). An agent has enough to call the tool correctly and interpret its output without surprises.

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 limit (default 50, max 500) and since (YYYY-MM-DD earliest approval date). The description restates that the cutoff is measured from each product's approval date, which is a mild clarification but largely duplicates the schema's own wording.

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 precise verb+resource+scope: newly registered therapeutic products in Singapore by HSA on or after a given date, ordered newest first. This is clearly distinguished from the sibling hsa_sg_product and hsa_sg_search, which do not carry the 'new registrations since date' framing.

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 gives clear usage context by delimiting scope ('Covers NEW REGISTRATIONS only') and explaining what is not visible (withdrawals, cancellations, variations). It does not, however, explicitly name an alternative tool to use when the user wants cancellations or variations, leaving that inference to the agent.

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