market_snapshot

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

Annotations already declare readOnlyHint=true, openWorldHint=true, and destructiveHint=false, covering the safety profile. The description adds that it is 'Powered by Yahoo Finance,' which is useful context about the data source. However, it doesn't provide additional behavioral details like data freshness, rate limits, or the scope of 'global' (e.g., which exchanges are included). Thus, it adds some value beyond annotations but not extensive behavioral transparency.

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 two concise sentences, front-loaded with the core purpose and supported by a data-source attribution. Every word earns its place, and there is no redundancy or fluff. It is well-structured and easy to scan.

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 zero-parameter, read-only tool with no output schema, the description is fairly complete: it specifies the asset classes and the data provider. However, it could be more complete by mentioning the return format, update frequency, or the fact that this is a broad snapshot versus a detailed analysis. Given the simplicity of the tool, the current description is nearly sufficient.

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?

There are zero parameters, and schema description coverage is 100% (since there is nothing to describe). The baseline for a zero-parameter tool is 4. The description doesn't need to explain parameters, and it doesn't. It does mention the output scope (what asset classes are covered), which partially compensates for the lack of parameters.

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 provides a global market overview with specific asset classes (indices, crypto, FX, ETFs). It uses a specific verb ('overview') and resource ('global market'), making the purpose clear. However, it doesn't explicitly distinguish itself from sibling tools like egx_market_overview or futures_market_overview, so it loses a point for lack of sibling differentiation.

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 provides no guidance on when to use this tool versus alternatives. There is no mention of when to choose market_snapshot over egx_market_overview, futures_market_overview, or other market analysis tools. The description simply states what it does without offering context on selection criteria or exclusions.

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