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

Goes well beyond the readOnlyHint annotation by enumerating what the call deliberately does NOT do: it does not unlock contact, does not consume quota, and returns no phone number, WeChat, or account payment token. It also states the login requirement and which fields are surfaced, so an agent knows both the positive return content and the guardrails.

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 dense, front-loaded clauses separated by semicolons; the purpose comes first and the negative guarantees follow, with no filler sentences. The dense punctuation-bound style is efficient though slightly cramped to parse.

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 single-parameter read-only tool with no output schema, the description supplies the action, the login requirement, the returned field categories, and the explicit non-effects. The remaining gap is sibling disambiguation against the several other contact-exchange tools.

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% for the single targetUserId parameter, and the description only implies its meaning via '指定用户' (the specified user). It adds no detail on acceptable identifier format, where the ID comes from, or behavior when the target is unreachable.

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 concrete read action and its object: viewing a specified user's in-app contact channel, opened direct-contact status, and human-assistance status, plus employee unlimited permission. It is clearly a status-check tool. Minor friction: the title says '查看本人' (self) while the description says '指定用户' (specified user), and no sibling such as get_contact_exchange_state is named to disambiguate.

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?

Usage is largely implied — this is a non-consuming status check, and the closing clause routes payment and human-assistance handling to the App, which is a partial when-not signal. However, it never states when to prefer this over nearby siblings like get_contact_exchange_state, request_contact_exchange, or get_quick_contact_context, leaving the agent to infer.

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