Stock Heatmap

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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, covering the safety profile. The description adds useful context about the response content (fields included) but does not disclose any additional behavioral traits such as pagination, rate limits, or output size. Given the annotations carry the safety burden, a 3 is appropriate for the value added.

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: two sentences. The core functionality is front-loaded in the first sentence, and the second clarifies the available index options. It is efficient, though the second sentence could be shortened by relying more on the schema, but it is not wasteful.

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 has a single optional parameter fully described in the schema, no output schema needed, and the description clarifies the response scope (all constituents with specified metrics). It is complete for an agent to call correctly, including the default index value. Nothing essential is missing.

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 100%: the 'index' parameter is fully documented with the default value and the complete list of allowed slugs. The description merely points to the parameter ('see the index parameter'), adding no extra semantic meaning beyond what the schema already provides. Baseline 3 is correct.

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 states a specific verb and resource: 'Get a stock heatmap for an index' and enumerates the exact data fields returned (market cap, PE, PB, price changes, volume, sector). This is a precise and differentiated purpose, clearly distinct from sibling tools like get_index_performance or get_index_history which focus on index-level data.

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 this tool: when you need a constituent-level snapshot for an index. It does not explicitly name alternatives or exclusions, but the context is clear enough for an agent to infer it is the right choice for heatmap-style data. No misleading guidance is present.

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