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

Annotations already declare idempotentHint=true and destructiveHint=false, so the baseline is low. The description adds real context beyond that: login is required, the operation is an upsert ('再次调用即编辑'), and there are preconditions about self-endorsement, unclaimed accounts, and mutual blocking. Only the response shape is left unstated.

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?

The description is a tight block that front-loads the login requirement and the core action, then lists the eligibility constraints. Every clause carries information an agent needs, and there is no filler or repetition.

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 description covers authentication, preconditions, and repeat-call behavior, which is what an agent needs to call it correctly. The only gap is that it does not indicate what the call returns, though that is largely a minor omission here.

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%, so all three parameters (userId, body, relation) are already documented in the schema. The description restates the body minimum of 4 characters and the optional relation but adds no format or example detail beyond what the schema provides, which is the expected baseline of 3.

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?

The description states a specific verb and resource: write a text endorsement (口碑) for a creator (主理人). It explicitly rules out a star rating ('无星级'), which separates it from the rating tools in the sibling list, and it names the target object unambiguously. It does not explicitly name a sibling to use instead, but the operation itself is clear.

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?

The description gives concrete eligibility conditions: you cannot endorse yourself or an unclaimed placeholder account, mutual blocking prevents writing, and one endorsement exists per pair with subsequent calls editing it. This tells the agent when the call will succeed and what happens on repeat. It stops short of naming alternative tools for adjacent actions such as following or rating.

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