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

With no annotations, the description carries the full burden and discloses the return fields, the UNKNOWN caveat for rate/REI/PPE, and the $0.05 per-call cost. It omits failure modes and auth requirements but covers key behavioral traits beyond the schema.

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 front-loaded with the core purpose, then lists returns, then caveats and pricing. Every sentence adds distinct value; there is no repetition or 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?

Given a single-parameter tool with no output schema and no annotations, the description is fairly complete: it details what is returned, what is not (UNKNOWN fields), and the cost. Minor gaps like error handling or auth expectations are less critical for a simple lookup.

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 0%, so the description must compensate. It provides an example format '(e.g. 66551-1)' which clarifies the expected pattern, but does not fully explain the regex or validation rules, making it adequate but not complete.

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, 'lookup,' and resource, 'US EPA pesticide product,' keyed by EPA registration number, with an example. It does not explicitly differentiate from siblings like check_state_registration or check_use_allowed, so a 4 rather than 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?

The description implies usage when an EPA registration number is known, and it explicitly warns that application rate, REI, and PPE are UNKNOWN until Phase 2, which helps avoid misuse. However, it does not name alternative tools or state when NOT to use this tool, leaving alternatives to inference.

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