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

The description discloses a notable behavioral trait: the cost of $0.001 USDC via x402. Since no annotations are provided, this adds transparency about payment requirements. However, it does not mention output format, error behavior, or other potential side effects, so coverage is partial.

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 exceptionally concise: two sentences with the first stating purpose and the second stating cost. Every word earns its place, and it is front-loaded with the core function.

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?

The tool is simple with one optional parameter and no output schema, so the description covers the basics. However, it omits the additional index options (sem10, demex) that appear in the schema, and it does not describe the return format. This is a minor gap for such a lightweight tool.

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 schema fully describes the only parameter ('index' with options semdex, sem10, demex and 'omit for all'), so the baseline is 3. The description adds no extra parameter semantics beyond the schema, which is acceptable given the 100% schema coverage.

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 a specific verb ('Get') and resource ('SEMDEX and SEM indices from Stock Exchange of Mauritius'), which immediately conveys the tool's function. This distinguishes it from sibling tools like forex_rates and fuel_prices by specifying the exact market and indices.

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 when to use the tool (when Mauritian stock market indices are needed), but it does not explicitly mention alternatives or when not to use it. There is no comparison with sibling tools or mention of exclusions, leaving usage context only implicit.

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