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

Annotations cover only the safety profile (readOnly/idempotent/non-destructive), so the description carries the rest and does so richly: tiered matching order, company-before-ETF and market-cap ordering within tiers, the 2-character minimum, code normalization (2330.TW/2330.TWO), and the fields each result carries. It also discloses the licensing/attribution obligation and that computed_by_livermore fields are not official figures, which no annotation conveys.

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-loaded with the core action, argument types, and follow-up tool in the first two clauses; the trailing conventions block (TWD, lots, _pct, Traditional Chinese, attribution) is long but each item is actionable for a Taiwan-market tool. Minor redundancy in enumerating result fields that the output schema already defines.

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 an output schema present, the description need not explain return values, yet it still frames them usefully. Combined with the routing guidance, currency/unit conventions, and attribution requirement, an agent has everything needed to call and correctly present results from this 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%, so the baseline is 3, but the description adds real semantics beyond the schema: query normalization rules, the 2-character threshold for name matching, and the tier hierarchy that determines which matches win. It does not restate the limit bounds, which is fine since the schema does.

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+scope: find Taiwan stocks and ETFs listed on TWSE or TPEx that are still trading, by code, Chinese short/full name, or English name. It explicitly positions itself as the entry point that produces the `code` consumed by every other tw_ tool, which cleanly separates it from tw_get_stock and from the US `search`/`get_stock`.

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?

Gives explicit when-to-use ('start here to get the code every other tw_ tool takes'), a named follow-up (tw_get_stock), and active exclusions ('Taiwan stocks are separate from the US tools (search, get_stock); TSMC's US ADR is TSM there'). An agent has no ambiguity about routing.

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