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

readOnlyHint=true already establishes the safe-read profile, so the description needn't restate safety. It does add meaningful context beyond annotations: the data is parsed from TDnet filings, exposes an 'extraction confidence' field and a source document reference, which hints at derived/probabilistic data quality — a genuinely useful disclosure. It stops short of describing ordering, coverage windows, or what an empty result means.

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 field enumeration is front-loaded and earns its place, but the entire content is duplicated verbatim in Japanese and the ISO 8601 format rule is spelled out twice, roughly doubling length. If bilingual output is a product policy this is defensible, but from a pure information-density view it is redundant.

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 two-parameter read tool with no output schema, the description usefully enumerates return fields and provenance, which compensates for the missing output schema. It is still incomplete on the operational details an agent needs: result ordering, whether all historical splits are returned, and the behaviour of the undocumented limit parameter.

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 only 50%: symbol is documented in the schema, but limit (default 50, max 100) has no description anywhere. The description adds no information about paging, ordering of returned events, or whether limit caps events per symbol — the gap that most affects correct invocation is left unfilled.

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 names a specific resource (stock split / reverse split events) and its source (TDnet filings), and enumerates the returned fields, so an agent knows exactly what this tool yields. It does not explicitly contrast itself with near-neighbours like get_disclosures or get_extraordinary_report_events, but no sibling returns split event data, so confusion risk is low.

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?

There is no when-to-use guidance, no prerequisite statement, and no mention of alternatives. An agent must infer from the resource name alone that this is the right call for split history rather than get_disclosures or get_events_feed.

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