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

Annotations already cover safety (readOnly/idempotent/non-destructive), but the description adds substantial non-obvious behavior: disclosures occur only at quarter-end plus ad-hoc material-change dates, and an empty window returns found:false naming the nearest disclosed dates rather than fabricating rows. That is exactly the kind of edge-case behavior an agent cannot get from structured fields.

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?

Front-loads the purpose and example queries before the critical caveat, and every clause carries load. It is slightly long with some repetition of Chinese/English field names, but nothing is truly expendable.

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?

With no output schema and a keyless external source, the description compensates by naming the returned fields, the source (Eastmoney fund F10, keyless), the disclosure cadence, and the failure mode. An agent has everything needed to call and interpret this correctly.

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 100% — code format/examples, from/to format and inclusive semantics, and defaults are all documented in the schema itself. The description reinforces the window semantics only by describing the empty-result behavior, adding little parameter syntax beyond what the schema provides. 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+resource (fund share-count and net-asset history for a Chinese-listed ETF), enumerates the exact fields returned (期末总份额, 期间申购/赎回, 期末净资产), and explicitly distinguishes itself from the daily-history sibling. An agent can route to it without opening the 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?

Explicitly names when to use it (share-count/AUM) and when not to ('For a daily PRICE series use ashares_daily_history'), and even pre-empts the misleading expectation by stating it is NOT a daily series. Full routing guidance is present.

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