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

Annotations already declare readOnlyHint=true, idempotentHint=true, openWorldHint=true, and destructiveHint=false, so the safety profile is covered. The description adds some useful behavioral context: a data contract version, exchange-local schedule selection, unknown prerequisites, and precedence of official exchange notices. It does not contradict the annotations, but it remains vague about return shape and edge-case behavior.

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 description is short and avoids unnecessary repetition. It is not perfectly front-loaded because the first sentence is a dense noun phrase rather than a clear action statement, but every sentence is brief and contributes some scope or caveat.

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?

There is no output schema, so the description should explain what the returned session templates and special hours look like, but it does not. It also leaves the required product parameter unexplained and does not clarify how this tool relates to the closely named sibling trading_day. For a two-parameter read-only tool with zero schema coverage, the definition is not complete enough.

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 0%, so the description must clarify both parameters. It explains that date selects the exchange-local schedule, which adds meaning for the date parameter. However, it does not explain the required product parameter beyond the undefined phrase 'FC product', leaving the most important required input under-specified.

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 points to session templates and special hours and says that the date selects the exchange-local schedule, so the resource area is inferable. However, it never states a clear verb such as 'get' or 'retrieve', and terms like 'FC product' and 'day-offset units' are left undefined. It also does not explicitly distinguish this tool from siblings such as trading_day or next_closure.

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?

The description gives one exclusion by saying there is no real-time market status or prices, which implies this is not a live-status tool. But it does not say when to choose this tool over trading_day, next_closure, or the notices tools, and there are no named alternatives or positive usage conditions.

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