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

Goes well past the readOnly/openWorld annotations: it discloses the exact billing model (12 credits per successful call, 1 credit = 1 CAD cent), that only successful calls are billed, that schema-invalid input is rejected before any charge, and that contact points are filtered to role mailboxes only. These are material traits an agent cannot derive from annotations or schema and that affect whether it should call at all.

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-loaded with purpose, then return shape, then the mailbox caveat, then cost — a sensible order with no filler. The inline return-object literal is dense but justified because no output schema exists to carry it.

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?

For a one-parameter enrichment tool with no output schema, the description covers purpose, return shape, privacy filtering and billing, which is close to complete. The remaining gap is routing context — nothing tells the agent how this differs from enrich-company or web-extract, which matters given the crowded sibling set.

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 the single 'url' parameter is thoroughly documented in the schema itself (pattern, length bounds, refused address classes), so the baseline is 3. The description adds only the qualifier 'public page' and does not, for example, say anything about redirects or what finalUrl implies for the supplied URL.

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 ('Profiles one public page') and enumerates exactly what is extracted (title, summary, entities, topics, sentiment, contact points), so the output domain is unambiguous. It never names or contrasts the closely related siblings (enrich-company, web-extract, page-markdown, sentiment, entity-extract), so an agent cannot rule those out from the description alone.

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?

There is no explicit statement of when to pick this over the many adjacent tools in the pack (enrich-company for companies, web-extract/page-markdown for raw content, sentiment/entity-extract for single-signal extraction). Usage is only inferable from the word 'Profiles', and no exclusions or preconditions (e.g. page must be publicly reachable and size-limited) are given.

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