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

Annotations already declare readOnlyHint=false, idempotentHint=true and destructiveHint=false; the description usefully explains WHY it is idempotent (one endorsement per pair, re-invocation edits). It adds the login/auth requirement and eligibility restrictions, though it says nothing about visibility, recipient notification, or failure behavior.

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-loaded with the login requirement and tightly written, but the parenthetical (无星级，文字必填 ≥4 字，可选关系 relation) largely duplicates what the input schema already states, spending space on redundant detail.

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 mutation tool with no output schema, the definition covers authentication, eligibility limits and upsert semantics well. Remaining gaps are minor: what the agent gets back, and whether the endorsement triggers notifications or moderation.

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 (body, userId, relation) are already documented, including the ≥4 char minimum. The description only restates those constraints and adds 'no star rating', which is baseline-level value given the schema does the heavy lifting.

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+resource (给主理人写口碑 / write a recommendation endorsement for a creator) with the exact output shape (no star rating, text-only). It is clearly a write operation distinct from get_creator_endorsements and rate_product, but no sibling is named explicitly, so it falls just short of the 5 bar.

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?

Explicit preconditions and exclusions: login required, cannot endorse yourself or unclaimed placeholder accounts, cannot endorse when mutually blocked. It also explains the one-per-pair rule and that a repeat call edits rather than duplicates, so an agent knows exactly when this tool applies.

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