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

Annotations already declare readOnly, idempotent, open-world, and non-destructive, so the safety profile is covered. The description adds genuinely new context: a concrete cost of $0.01 per call, which materially affects invocation decisions for an agent. It omits failure behavior for unknown or parked domains and whether results are cached.

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 sentences with zero filler: the capability and output scope come first, then the cost. The field enumeration is long but earns its place since there is no output schema to describe the return payload.

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 properly compensates by listing returned fields, and it discloses pricing. It leaves minor gaps around error handling for invalid domains and whether the call is synchronous, but an agent has enough to decide and invoke 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?

There is a single parameter with 100% schema description coverage including a format example (figma.com), so the schema carries the semantics. The description reinforces "just a domain" and frames it as the sole input, which is useful confirmation for a one-parameter tool.

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 ("Build a company profile from just a domain") and then enumerates exactly what the profile contains: name, description, logo, location, socials, contact info, domain age, providers, tech stack, and business signals. That enumeration clearly separates it from narrower siblings like domain_report, tech_stack, and domain_whois.

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?

"One call instead of six" gives a clear usage cue that this is the bundle to reach for when multiple data points are needed, rather than stitching together the granular siblings. It stops short of naming which siblings it replaces or when a narrower tool would be preferable.

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