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

With no annotations provided, the description carries the full burden of behavioral disclosure. It indicates a read-only operation via 'View' and 'Check', but does not describe the return format (e.g., list, map), timezone handling, or any limitations such as data freshness or coverage. This is adequate but leaves significant gaps.

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 extremely concise, consisting of two short sentences that immediately communicate the tool's purpose. There is no wasted information, and it is front-loaded with the key action ('View the market hours for all exchanges').

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?

Given the tool's simplicity (no parameters, no output schema), the description is minimally sufficient. However, it could provide more context about what 'market hours' includes (e.g., regular vs extended hours) and the expected output structure. The existence of a similar sibling (getExchangeMarketHours) suggests this tool's unique value should be more explicit, but the description does not clarify the 'all' versus 'single' distinction beyond the name.

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?

The tool has zero parameters and an empty input schema, so the baseline is 4. The description correctly avoids adding parameter details, as there are none to explain. The schema coverage is 100% (vacuously), and no parameter semantics are needed.

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 clearly states the tool's function: 'View the market hours for all exchanges' and 'Check when different markets are active.' It uses a specific verb and resource, and the name reinforces the 'all' scope. However, it does not explicitly distinguish itself from the sibling tool 'getExchangeMarketHours', which may target a single exchange.

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 implies usage when one needs market hours across all exchanges ('Check when different markets are active'), but it provides no explicit guidance on when to use this versus alternatives like getExchangeMarketHours or getHolidaysByExchange. There are no exclusions or alternative suggestions.

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