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

Annotations already declare readOnlyHint, idempotentHint, openWorldHint, and non-destructive behavior. The description adds value beyond annotations by specifying the output content ('current ADI and functional class') and the temporal nature ('most recently added or re-evaluated'), which helps an agent understand what to expect from the result.

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 two concise sentences with no wasted words. The primary action is front-loaded ('Show...'), and the usage guidance is right after, making it highly 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?

For a zero-parameter tool with no output schema, the description adequately describes the return content (substances with ADI and functional class) and the recency scope. It doesn't specify result count or sorting order, but 'most recently' implies chronological order, and the openWorldHint annotation covers dynamic data. This is sufficient for an agent to invoke 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?

The tool has zero parameters, so the baseline is 4 by the rubric. The description does not need to explain parameters, and the schema is empty, so no additional parameter meaning is required.

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 states a specific verb and resource: 'Show the substances most recently added or re-evaluated by JECFA' and includes the content ('current ADI and functional class'). It clearly differentiates this recent-evaluation listing from the lookup-oriented siblings through the 'rather than to look up a known substance' contrast, so an agent can tell it apart from jecfa_search or jecfa_by_number.

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 second sentence gives an explicit when-to-use ('check what the committee has looked at lately') and when-not-to-use ('rather than to look up a known substance'). This provides clear context for selecting this tool over alternatives, even though it doesn't name a specific sibling tool.

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