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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint=false, so the safety profile is covered. The description adds behavioral context by stating what the tool returns (medicine, current status, last-updated date) and what kinds of register changes are included, going beyond the bare annotation signals.

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?

The description is three sentences with no filler. The core concept is front-loaded, the return fields are stated in the second sentence, and the example questions in the third sentence make the tool's use case immediately scannable.

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 explains what the agent can expect in the result: the medicine, its current status, and the last-updated timestamp. Given the simple optional-parameter surface and rich schema examples, the description is complete enough for an agent to select and invoke the tool 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%, so the schema already documents all four parameters (limit, since, status, category) with descriptions and examples. The tool description adds no additional parameter-level detail beyond hints like filtering by withdrawn/suspended status, so the baseline of 3 is appropriate.

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 names a specific resource (European Medicines Agency register entries) and a specific verb (changed), then enumerates the change types: new authorisations, withdrawals, suspensions, and refreshed product information. It clearly differentiates this from sibling tools like ema_recent_approvals, which only cover approvals.

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 provides concrete example questions such as "what changed at the EMA this week" and "which EU medicines were recently withdrawn or suspended," which gives an agent clear context for when to use it. It does not explicitly name alternatives or state when not to use it, but the intent is sufficiently clear.

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