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

Annotations already indicate a safe, read-only, idempotent operation. The description adds valuable behavioral context by listing the exact output fields (reason, local time, session, next open/close) and disclosing that Sun–Thu markets and holidays are handled. No contradictions with 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 description is concise, front-loaded with the purpose question, and each sentence adds relevant information—purpose, return fields, and market handling—without any wasted words.

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 (one parameter, read-only, with annotations), the description is complete for an agent to understand what it does and what it returns. It explicitly lists the return fields and notes holiday handling, which is sufficient in the absence of an output schema.

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 input schema fully covers the single parameter 'exchange' with examples (NGX, JSE, EGX), so schema coverage is 100%. The description does not add any additional meaning about the parameter itself, meriting the baseline score of 3.

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: checking if an African exchange is open right now. It specifies the resource (African exchange) and the return content (reason, local time, session, next open/close), distinguishing it from sibling tools like get_ngx_market_status by its African-wide scope.

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 the use case (checking market open status for African exchanges) and notes a limitation (handles Sun–Thu markets and holidays), but it does not explicitly state when to use this tool versus alternatives or when not to use it. No alternatives are named.

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