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

Annotations already declare readOnly, idempotent, openWorld and non-destructive, so the safety profile is covered. The description adds a genuinely useful behavioral fact not in structured data: "free, no key" (access/auth requirement). It stops short of rate limits or result-size/pagination behavior, which matters for a public API.

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?

Two tight sentences, front-loaded with the action and resource, then returns, then usage. Every clause earns its place with no filler.

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?

An output schema exists, so return values need not be explained yet are helpfully summarized; access cost ("free, no key") is disclosed. The remaining gap is operational detail (rate limits, pagination/caps beyond the schema's max 100) for a high-volume public API.

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 both parameters (limit, query) are documented in the schema, including a syntax example. The description adds no parameter-level meaning beyond that, so the baseline 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?

States a specific verb and resource: query openFDA drug adverse-event reports, and even names the source (FDA FAERS). It also lists the returned fields, which makes the scope unambiguous against siblings like pubchem_compound or clinicaltrials_study. It never explicitly names an alternative tool, so it falls short of a 5.

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?

"Use for pharmacovigilance signals from the FDA FAERS data" gives a clear use context, but there is no when-not guidance and no named alternative for overlapping queries (e.g., drug identity vs. adverse events). Usage is implied rather than routed.

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