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

Annotations already establish read-only, idempotent, non-destructive behavior. The description adds useful behavioral context by indicating the tool returns a 'complete' record containing 'every safety evaluation JECFA has made,' which is more than a simple single-row lookup. It does not mention edge cases like missing ids, but the annotation coverage is strong.

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 a single dense sentence with the core purpose front-loaded and the content list following. Each listed data field is useful because there is no output schema, though the sentence is somewhat long and the list could arguably be trimmed without losing meaning.

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 single-parameter lookup tool with rich safety annotations and no output schema, the description is complete: it identifies the exact input source, enumerates the full expected response content, and gives the intended use case. No critical information is missing 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% and the only parameter id is already described as 'Chemical id from jecfa_search (e.g. 62 for aspartame).' The description's mention of 'chemical id' adds no new semantic detail beyond what the schema provides, so the baseline score of 3 applies.

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 uses a specific verb ('Fetch the complete JECFA record') and clearly identifies the resource and input ('one substance by its chemical id'). It enumerates the exact contents returned, making the tool's function unambiguous and distinguishing it from sibling search tools by its one-substance, complete-record scope.

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 explicitly states when to use the tool: 'Use after search to explain how and when an ADI was set or revised.' This gives clear contextual guidance, though it does not explicitly contrast the tool with jecfa_by_number or jecfa_by_functional_class or state when not to use it.

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