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

Annotations already declare readOnlyHint, idempotentHint and openWorldHint=false, so safety is covered. The description adds real behavioral context beyond that: the statistics are drawn from the US universe, each event comes with a sample size, and small samples are flagged as caution-worthy.

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 dense sentences, front-loaded with the primary purpose and followed by what is returned per event and the small-sample caveat. Nearly every clause earns its place, though the parenthetical example list could be trimmed.

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?

An output schema exists, and the description still usefully previews the return shape (forward returns at 1w/1m/3m/6m/1y, sample size, unconditional baseline), which helps the agent judge relevance. It is complete enough for a single-parameter read-only 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?

Only one parameter (ticker) and schema description coverage is 100%, so the schema fully documents it. The description adds the implicit scoping of 'on a ticker today' but no format or syntax detail beyond the schema, so the 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: historical base rates for technical events firing today, with concrete examples of the event types (RSI below 30, golden/death cross, 52-week high/low). This clearly separates it from siblings like get_technical_indicators, which report current indicator state rather than historical forward-return statistics.

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?

Provides clear usage context via the quoted question it answers, 'what usually happened after this', which tells the agent the intended analytical framing. It does not, however, state when not to use it or point to an alternative sibling for current indicator values or raw price history.

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