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

Annotations only declare readOnlyHint and openWorldHint. The description adds substantial behavior beyond that: it is live/real-time data sourced directly from regulators, it enumerates the exact market-summary contents returned, and it discloses the licensing constraint that blocks CA/AU/HK/IN. This is genuinely useful context an agent couldn't infer from the annotations.

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 purpose and the ticker/no-ticker behavior are front-loaded, and the regional enumeration is informative rather than padding. It is a dense single block, and the trailing version tag 'v5.732' is pure noise, but overall little is wasted.

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 no output schema, the description carries the return-value burden and does so well by describing the market-summary payload. It is close to complete for a read-only, 4-param tool, with the only meaningful gap being the unexplained `days` and `side` semantics.

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 25% (only `ticker` is described in-schema). The description compensates for some of this: it clarifies that `ticker` also accepts company/insider names and maps `market` regions to their regulators while noting the unsupported ones. However, it says nothing about `days` or the `side` enum values (trades/sell/buy/proposed/exercise/all), leaving half the parameters unexplained.

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 verb and resource ('Live insider trades read straight from the regulators') and enumerates exactly what data it covers — SEC Form 4, Form 144, BaFin, AMF, Finansinspektionen, AFM, EDINET. An agent can clearly distinguish this from siblings like get_market_radar or get_money_flows 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?

It states the two operating modes with clear conditions: 'Without a ticker it returns the market summary… With a ticker, company or insider name it returns that name's filings.' It also flags region caveats ('Canada, Australia, Hong Kong and India… need a data licence first'), though it names no alternative sibling tool for those cases.

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