Weekend and overnight gaps: stock, index and commodity perpetuals against the cash close, checkpoint by checkpoint

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

Annotations already declare readOnlyHint=true and openWorldHint=true, so the safety profile is covered. The description adds useful behavioral context beyond annotations: the data comes from ByKaranteli's own ten-minute venue record, output is checkpoint-by-checkpoint, and it reports venue disagreement plus the next-open realised gap.

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 definition is two compact sentences with no wasted wording. The call condition is front-loaded, and the data-source/parameter scope is compressed into the second sentence without diluting the message.

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 query tool with no output schema, two optional parameters, and full schema coverage, the description is complete enough. It explains the purpose, the intended user question, the data source, and the conceptual outputs an agent should expect.

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 description coverage is 100%, and both parameters are already well documented there, including the symbol pattern and the weekend/night enum. The description repeats the window choices and whole-board default but adds no extra syntax, constraints, or examples beyond the schema.

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 states a specific resource and scope: weekend/overnight gaps for stock, index, or commodity perpetuals versus the cash close, with checkpoint-level distance, venue disagreement, and next-open realised gap. It clearly distinguishes this query from a broad board query, but does not explicitly name a sibling alternative to differentiate from.

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 gives an explicit trigger: 'Call this when the user asks what a stock, index or commodity perpetual did over the weekend or overnight while the cash market was closed...' This is clear context, but it does not state when not to use the tool or name a preferred alternative among the many get_* siblings.

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