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

With only destructiveHint=false in the annotations, the description carries real behavioral weight: it defines the actor roles (current user sends, original author receives), the authorization scope required, and a firm impersonation ban. It does not say whether the recipient gets a notification, whether the send is reversible, or what happens on a duplicate send, which keeps it below a 5.

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 four short clauses with no filler, and the key precondition is front-loaded in the first sentence. The mutual-exclusivity rule is tacked on at the end without a lead-in, which slightly weakens the structure.

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 send/mutation tool with no output schema and no parameter documentation in the schema, the description covers the trigger conditions and authorization well. However, it omits the effects on the recipient, the idempotency behavior, and the meaning of two of the four parameters, so an agent could still call it incorrectly.

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%, so the description must document all 4 parameters. It only explains that planId and shareAccessId are mutually exclusive ('二选一'); it never says what each identifier refers to, and it leaves 'note' and 'expectedUpdatedAt' (the latter is evidently a concurrency token) completely unexplained.

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 conveys that this tool sends a cooperation-interest message to the plan author, and it names both the sender and the receiver ('当前用户是发送方、原作者为接收方'). The purpose is clear, but the description never explicitly names the resource being sent (合作意向), and it does not distinguish this tool from close siblings such as send_cooperation_request or respond_cooperation_request.

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?

It gives an explicit precondition ('仅用户明确指示联系方案作者时发送') and a hard limit on the authorizations that make the call valid (only for public plans or the user's own valid share access). It also states an exclusion: never send an invitation on the original author's behalf. When to call, when not to call, and the guard conditions are all spelled out.

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