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

With no annotations provided, the description carries the full disclosure burden. It delivers meaningful behavioral traits: the operation is read-only (查看), requires no authentication (无需 App Key), and is free (免费). This is strong coverage for a zero-parameter info tool, though it omits response format and any pagination or rate-limit 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?

A single compact sentence conveys the full purpose with usage conditions in parentheses. The core action is front-loaded, and every clause carries information — no filler, no repetition of the tool name, no wasted words.

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 tool with zero parameters, no annotations, and no output schema, the description is complete: it names exactly what information is returned (introduction, billing, contact) and the preconditions (free, no App Key). Nothing an agent needs to invoke it correctly is missing.

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?

The tool has 0 parameters with 100% schema coverage, which sets the baseline at 4. There are no parameter semantics to add, and the description correctly avoids inventing any — nothing is lost by the description staying silent on parameters.

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 uses a specific verb (查看/view) and resource (服务介绍、计费方式与联系方式 = service introduction, billing, contact info), giving the tool a concrete scope. The domain clearly differs from the sibling invoice tools (invoice_confirm_issue, invoice_create_draft, invoice_query), so an agent can distinguish it without opening any schema.

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 clear prerequisite guidance — 无需 App Key，免费 (no App Key required, free) — telling an agent this tool needs no authentication setup and has no cost. However, it does not explicitly state when to prefer this tool over alternatives or when not to use it; the relationship to the invoice siblings is implied only by domain difference.

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