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

Annotations already cover readOnly/idempotent/non-destructive, so the bar is lower; the description adds meaningful context by disclosing the upstream source (TWSE/TPEx open data) and enumerating the returned fields, which matters since no output schema exists. It does not state data freshness or how the daily close is timed, which is a minor gap.

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?

Three sentences, front-loaded with what the tool returns, then the accepted input forms, then concrete example queries. Every sentence earns its place with no filler.

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 one-parameter read tool with no output schema, the description adequately explains both the input forms and the returned fields. The main omission is any note on data freshness or latency, which an agent may want for a 'daily close' tool.

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% for the single parameter, and the description's accepted-format list (numeric code, English abbreviation, Chinese name) and 20-per-call cap largely restate the schema's own description rather than extend it. Baseline 3 is appropriate when the schema already carries the parameter documentation.

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 precise resource (daily OHLC + change + volume + TWD turnover) and scope (Taiwan-listed stocks and ETFs, TWSE/TPEx), which cleanly separates it from siblings like taiwan_market_summary and taiwan_top_traded. An agent can identify exactly what data it returns 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?

The example questions ('what did TSMC close at', 'price of 2317', 'how did Taiwanese stocks trade today') give clear context for when to reach for it. However, it never names an alternative or an exclusion, so the agent must infer the boundary against taiwan_market_summary, taiwan_search_securities and taiwan_stock_valuation on its own.

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