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

Beyond the annotations (readOnly/openWorld/idempotent/non-destructive), the description adds genuinely useful behavior: a hard cap of twenty records, no pagination, a daily per-caller quota, and an explicit auth convention (X-Payment / X-Payment-Tx / Bearer fg_… in request headers, not in arguments). It does not explain quota-exhaustion or error behavior, 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?

Content is duplicated across [zh] and [en] blocks, wrapped in decorative pipes and full-width punctuation, and the actual purpose is not front-loaded — it appears after an odd quoted example. The payment-header note is useful but arrives last; substantial trimming and restructuring would make this far more scannable.

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 zero-argument, read-only preview with no output schema, the definition covers the essentials: sample size, cost model, quota, and auth placement. It leaves gaps an agent would care about — what fields a sample record contains, and whether the twenty models are fixed or vary per call.

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?

There are zero parameters, so the baseline is 4. The description's "Args: none" is consistent with the empty schema and reinforces that the payment/auth material must not be passed as 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 definition conveys a preview that returns a fixed set of twenty real OpenRouter model pricing samples, and the vendor asset name "AI 模型定价 · 私有源站单源试点" identifies the resource (AI model pricing). However, the core purpose is buried in a bilingual, pipe-delimited block and the opening example phrase ("Ask 'show twenty pricing samples'") reads as a user utterance rather than a tool description, so the verb+resource is only indirectly stated.

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?

"不支持翻页或全量检索" (no pagination or full retrieval) implicitly routes full-data needs elsewhere, and the free/per-caller daily quota hints at when a preview is appropriate. But no sibling is named and no explicit when-to-use/when-not-to-use statement is given; the agent must infer that export covers the excluded full-retrieval case.

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