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

Annotations already declare read-only, idempotent, non-destructive, open-world behavior, so the safety profile is covered. The description adds genuinely non-obvious operational facts: the asset is free with a daily per-caller quota, and payment/auth headers (X-Payment, X-Payment-Tx, Authorization: Bearer fg_…) must go in MCP request headers rather than parameters. Those are the kind of failure modes an agent would otherwise hit.

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 purpose and content summary are front-loaded, which is good, but the same information is then restated in Chinese and English blocks, and the parenthetical quota note repeats 'free' from the opening line. Roughly a third of the text is duplication rather than added signal.

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 parameterless, read-only digest with no output schema, the description covers what the digest contains, its cost/quota model, and how to authenticate — enough to call it correctly. The remaining gap is how this digest differs in scope from the sibling listing tools, which an agent would need to pick confidently.

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?

Zero parameters, so the baseline is 4, and the description confirms this explicitly ('入参：无' / 'Args: none') and separately clarifies that payment material belongs in headers, not in the argument object. Nothing further is needed for a parameterless call.

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 states a specific resource and angle: a digest answering 'which exchange is cheapest to list on', covering zero-fee declarations, realistic token budgets, intermediary blacklists, and review speed plus top-3 exchange summaries. That is a concrete, distinguishable purpose, though it never names or contrasts the sibling tools (listing_intel, exchange_matrix_entry, anti_scam_check) that likely overlap heavily.

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?

Usage context is implied — 'free, daily per-caller quota' tells the agent this is the no-cost snapshot entry point, and the payment-header note tells it how access works. There is no explicit when-to-use vs when-to-use-something-else guidance, no statement of what the paid or per-exchange alternatives provide, so selection between the several listing-info siblings is left to inference.

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