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

Annotations only carry generic hints (readOnlyHint=false, idempotentHint=true, destructiveHint=false), so the description carries the behavioral burden and delivers: requires login, takes effect immediately with no review process, links is a wholesale group replacement rather than a merge, and an empty canOffer removes the user from the matching pool. No contradiction with annotations.

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 well-structured paragraphs: the first front-loads operational facts (login, immediate effect, partial update, links replacement, alternatives, read-first workflow); the second delivers the high-stakes canOffer policy with a vivid example that earns its length. Minor redundancy exists where the matching-axis explanation repeats the schema's canOffer description.

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?

Complete for an all-optional profile-update tool: prerequisites, effect timing, replacement semantics, sibling routing, and the one field whose emptiness has product-wide consequences are all covered. There is no output schema, but return-value shape is low-risk for a simple update operation and the operationally critical knowledge is present.

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 57%; the description adds the crucial partial-update semantic ('所有字段可选，只传想改的') and the replacement semantics for links. It enriches canOffer with a concrete before/after example and the 'don't leave empty' warning, though some of the matching-axis phrasing duplicates the schema's canOffer text. The three undocumented params (location, nickname, avatarUrl) are self-evident from their names.

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 ('更新当前用户资料' — update the current user's profile) and adds the key scoping detail that it is the current user's own data, effective immediately. It names sibling tools handling adjacent operations (add_profile_link, remove_profile_link, get_my_profile), so an agent can separate it from the large sibling list without opening other schemas.

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 explicit when-not/alternative guidance: for single-link add/remove, use add_profile_link or remove_profile_link instead of passing the whole links array. Recommends a concrete read-before-write workflow (get_my_profile first) and instructs agents to always populate canOffer when onboarding/curating a user's profile, with the consequence of leaving it empty.

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