get_fundamentals

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

Annotations already declare readOnlyHint and openWorldHint. The description adds useful context: data source (Alpha Vantage OVERVIEW), 24h cache with rationale, and 404 return for unsupported instrument types. This goes beyond the annotations but does not cover rate limits or response formatting.

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 verbose due to a long enumeration of fundamental metrics, which is likely redundant given the output schema exists. It could be condensed to metric categories plus source/caching/error details. The second sentence adds value, but the first sentence is overly detailed.

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 simple one-parameter read-only tool with an output schema, the description covers the purpose, data source, caching behavior, and invalid-input error conditions. It does not mention rate limits or authentication, but these are not critical given the annotations and tool simplicity.

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 already describes the ticker parameter with an example (100% coverage). The description supplements this by clarifying that only US equities with SEC filings are valid and that ETFs/futures/crypto return 404, adding meaningful constraints on parameter values.

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 identifies the tool as providing company fundamentals for a single US equity and enumerates specific metrics, making its purpose unambiguous. It distinguishes from sibling tools like get_quotes or get_history by focusing on fundamental data rather than price/volume.

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 usage for fundamental analysis by listing metrics, but it does not explicitly state when to use this tool over alternatives. It provides constraints (US equities with SEC filings) and error behavior, but no clear 'use this instead of X' guidance.

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