get_historical_fng_tool

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 mentions that the number of days is 'limited by the API,' which hints at potential constraints, but doesn't specify rate limits, authentication needs, error conditions, or what happens if the limit is exceeded. For a data retrieval tool with zero annotation coverage, this leaves significant behavioral 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 well-structured and appropriately sized, with a clear purpose statement followed by parameter and return sections. Every sentence adds value, and there's no redundant information. It could be slightly more front-loaded by emphasizing key constraints earlier, but overall it's efficient.

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 moderate complexity (single parameter, no output schema, no annotations), the description is adequate but has gaps. It explains the parameter and return type, but lacks details on behavioral aspects like error handling or API limits. Without annotations or output schema, it should ideally provide more context on what the returned data looks like (e.g., format, structure).

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 description adds meaningful context for the single parameter 'days' by explaining it represents 'Number of days of historical data to retrieve' and noting it's 'limited by the API.' Since schema description coverage is 0% (the schema only provides type and title), this compensates well by clarifying the parameter's purpose and constraints, though it doesn't specify exact limits or formats.

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 purpose: 'Get historical CNN Fear & Greed Index data for a specified number of days.' It specifies both the verb ('Get') and resource ('historical CNN Fear & Greed Index data'), making it easy to understand what the tool does. However, it doesn't explicitly differentiate from sibling tools like 'get_current_time' or 'get_price_history' that might also retrieve time-series 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 provides no guidance on when to use this tool versus alternatives. It doesn't mention sibling tools like 'analyze_fng_trend' (which might process this data) or 'get_current_time' (which might provide different temporal data), nor does it specify prerequisites or exclusions. The only implicit usage hint is the parameter description mentioning API limits.

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