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

Annotations already communicate read-only and idempotent behavior. The description adds value by clarifying this never contacts the business and that the data reflects a stored record ("when the record was last verified"). This is useful context beyond the annotations.

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, front-loaded with the core action and output, followed by a clarifying behavioral note. No filler or redundant detail.

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?

With no output schema, the description names the returned data categories (contact channels, capabilities, last verified timestamp). It sufficiently sets expectations for a simple lookup tool, though it could clarify the optional capability parameter's role.

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 carries the full burden for parameterscy. It mentions 'a business' and 'capabilities' but does not explicitly explain what `smb_id` should contain or how `capability_to_verify` affects the lookup. The optional parameter's meaning remains ambiguous.

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 clearly states the tool is for looking up known business information in the supply network, with specific outputs named (contact channels, capabilities, last verified record). The explicit 'DIRECTORY LOOKUP - it does not contact the business' removes ambiguity about whether this is a live verification or a passive query.

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 gives clear usage context: it is a read-only directory lookup, and explicitly says it does not contact the business. It does not name alternative sibling tools for comparison, but the exclusion is enough to prevent obvious misuse.

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