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

With no annotations, the description must carry the behavioral burden. It usefully discloses the returned data shape (ex-div dates, cash dividend, last close, estimated yield) and that results can be filtered by minimum yield, but says nothing about the read-only nature, default/all-code behavior when code is omitted, or any limits.

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?

A single front-loaded sentence that packs purpose, returned fields, and the filter capability. The bracketed category tag is minor overhead but the sentence itself has no wasted clauses.

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 read-only lookup with no output schema and no annotations, the description covers the data returned and the optional filter, which is adequate. It leaves open what happens with no code supplied (all stocks?) and does not route the agent among the crowded sibling dividend tools.

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 code, days, and min_yield are already documented in the schema (including the 30/120-day bounds and the % unit). The description only echoes the min_yield filter, adding no syntax or semantics beyond the schema, so 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 and resource: querying Taiwan-listed stocks and ETFs' upcoming ex-dividend calendar, enriched with cash dividend, last close, and estimated yield. This distinguishes it from siblings like get_tw_ex_dividend (bare calendar) and get_tw_dividend, though it never names them explicitly.

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?

No statement of when to use this versus the several adjacent dividend tools (get_tw_dividend, get_tw_ex_dividend, get_etf_dividends, estimate_etf_dividend_2027). Usage is only implied by the described output fields; there are no exclusions or prerequisites.

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