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

Annotations only declare idempotentHint and destructiveHint=false, so the description carries the real burden and does well: it discloses the login requirement, the OWNER/ADMIN authorization gate, that appointing or touching a current ADMIN is owner-only, that the owner's own role is immutable, and that certain official roles are tenure-bound and cannot be edited. It stops short of saying what the call returns or what happens on a failed authorization check, but the mutation's blast radius and permission model are clear.

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-loads the highest-value signal (login + OWNER/ADMIN) in a bracketed tag, then purpose, then the ID-sourcing workflow, then the immutability caveats. Dense but every sentence carries a constraint an agent could otherwise get wrong; only the membershipId/userId note is redundant with the schema.

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 three-parameter mutation with no output schema, the definition covers authorization, ID sourcing, user-confirmation protocol, and all known immutable cases, so an agent can act correctly. The main remaining gap is that it never says the owner-only rules apply to ADMIN specifically versus all role changes, nor what a success response contains.

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%, so the baseline is 3; the description earns a step above it by glossing each enum value in Chinese (管理员/活动负责人/撮合员/MEMBER), giving the agent the human meaning of the roles it must confirm with the user. The 'membershipId is not userId' warning duplicates the schema field description, so it adds no new information.

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 ('把一位在册成员设为' one of four named roles) and enumerates all four target roles, which map exactly to the schema enum. An agent can distinguish it from remove_organization_member, invite_organization_members and update_my_organization_membership from the text 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?

Gives an explicit prerequisite chain: call list_organization_members to obtain membershipId, read it back to the user for confirmation, then call this tool. It also names the alternatives for cases it cannot handle (role change of the owner → transfer ownership in App/web; official role assignments → immutable), which is exactly the when-not guidance most definitions omit.

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