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

Annotations already cover readOnly, idempotent, non-destructive and closed-world behavior, so the bar is low. The description still adds genuinely new facts: that it performs no contact, the acceptable id namespace, and cost/access tags '[free, no key] [limited]' signaling no credentials but constrained availability. The '[limited]' tag is left undefined, which keeps it from a 5.

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?

Front-loads the lookup scope, then the disambiguating negative, then the id constraint and cost tags - a sensible ordering with no filler sentences. The bracketed tags are terse and functional, though '[limited]' is vague enough to cost a point.

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 compensates by naming the returned content (contact channels, capabilities, last verification), and annotations carry the safety profile. The remaining gap is the unexplained capability_to_verify parameter, which an agent may need to call 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 coverage is 0%, so the description must carry both parameters. It does document the smb_id namespace constraint ('Supply-network ids only, not osm:... ids'), which is real added meaning. However, capability_to_verify is never explained - no hint of what capabilities exist or what verification means for them - leaving half the parameters undocumented.

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 ('Look up what we know about a business in our supply network') and enumerates the fields returned (contact channels, capabilities, last verification). It also draws the key boundary against siblings by declaring 'A DIRECTORY LOOKUP - it does not contact the business', which separates it from call_business without opening either schema.

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?

Gives clear context for when the tool applies: read-only directory inspection rather than outreach, and id-namespace restriction ('Supply-network ids only, not osm:... ids'). The alternative (call_business) is implied by the negation but never named explicitly, so an agent must infer the routing rather than being told it.

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