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

Annotations already declare readOnly/idempotent/non-destructive, and the description goes well beyond them: assertion_class is always 'inferred', coverage is one Rhea plus one Human-GEM release, hub compounds return counts only, unlinked participants and human-enzyme-only listing, plus the empty-result interpretation. This is unusually rich behavioral context.

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?

Long but front-loaded and dense: the identity of the data, the 'inferred' caveat, and the routing to get_findings come first, with edge cases after. Only the coverage sentence is somewhat sprawling, but nearly every clause carries distinct information.

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 read-only lookup with no output schema, the description supplies everything needed: row semantics, hub-count exception, participant linkage rules, and empty-result meaning. An agent can interpret results correctly without an output schema.

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 coverage is only 33% (node_id documented, limit/offset not), so the description needs to compensate but does not: it adds no meaning about limit, offset, or pagination behavior. The node_id example lives in the schema, not the description.

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: biochemical reactions from Rhea/Human-GEM that a compound or protein participates in, with the direction (substrate/product vs catalyses/transports) spelled out. It clearly distinguishes itself from the sibling get_findings by naming it as the tool for effects.

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?

Explicitly says to use this tool for biochemistry but get_findings for effects, warns never to present rows as an effect or recommendation, and explains the hub-flag special case and what an empty result means. Both when-to-use and when-not-to-use are covered.

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