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

The only annotation is destructiveHint=false, so the description carries most of the burden, and it does disclose that accept=true reveals a snapshot of contact details taken at that moment and cannot be undone, plus idempotency on repeats. What it omits is what the caller receives back, any notification sent to the counterpart, and whether the original requester sees the rejection reason. Useful but not rich.

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?

Four compact clauses with the precondition and the state-check workflow front-loaded and no filler. Density comes at a cost: the leading '登录' and '本人至少一项联系' are telegraphic, and the flow diagram is compressed into a single arrow chain that takes a second read to parse.

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 3-required-parameter mutation with no output schema, the description covers the precondition, the irreversible branch, and the recommended state check, which is most of what an agent needs to call it safely. The main missing piece is the return value or confirmation behavior, since no output schema exists to fill that gap.

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% and the schema already documents accept (true=agree, hands over contact info, irreversible; false=decline), exchangeId, and the 1-to-1 conversationId restriction. The description paraphrases the accept semantics rather than adding new detail such as what the 'contact snapshot' contains or which contacts qualify as 'at least one'. Baseline 3 applies.

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: reply to a real person's pending contact-exchange request in a 1-to-1 DM, and the accept=true branch is spelled out. An agent can distinguish it from request_contact_exchange and from the many other respond_* siblings. It stops short of explicitly naming the sibling counterparts, so it is clear but not maximally differentiated.

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 the exact workflow: get_contact_exchange_state → confirm → respond, plus the precondition that accept=true requires explicit user confirmation and the user must have at least one contact on file. It also states reject can be re-requested later and that repeated responses are idempotent, so both paths and their constraints are covered.

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