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

readOnlyHint=true already tells the agent this is a safe read. The description adds that only 'public' contact data is returned (implying no private fields) and enumerates the returned categories, which is useful. It says nothing about authentication, rate limits, or fallback behavior when a channel is missing, so it is adequate but not rich.

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?

One short sentence with the returned data categories front-loaded and no filler. It is efficient, though it sacrifices some usefulness for brevity rather than being a model of structured guidance.

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?

No output schema exists, so the description carrying the list of returned fields is helpful, and annotations cover the safety profile. However, with an optional filter parameter and siblings that overlap in retrieval intent, the definition leaves selection and filtering behavior underspecified.

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 100% — the single 'channel' parameter is fully documented with its enum-like values in the schema. The description adds no syntax or format detail beyond that, so the baseline 3 applies.

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 ('Return') and the resources returned (public email, phone, booking links), which is clear enough to distinguish from book_a_conversation and search_public_facts. It does not explicitly name or differentiate against the sibling get_profile, which also sounds like a retrieval tool, so it falls short of a 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?

There is no when-to-use, when-not-to-use, or alternative-routing guidance. An agent must infer that this is the tool for obtaining contact details versus get_profile. No exclusions or conditions are stated.

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