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

Annotations already define this as readOnly, idempotent, and non-destructive, so the description doesn't need to repeat those. It adds the intraday 60-day limitation and default values, which are useful, but it does not disclose other behavioral aspects like data source, rate limits, or error conditions. The additional context is modest, so a mid-range score is appropriate.

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 front-loaded with a clear purpose sentence and then structured as an Args list. It is concise and every section provides necessary detail without excessive verbosity. The only minor redundancy is listing the output fields, which may be covered by the output schema, but it still adds value.

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 read-only tool with an output schema, the description covers key invocation details: ticker example, period and interval valid values with defaults, and a critical data constraint. However, the unsupported 'start and end' mention and lack of error conditions or date format specifics leave some gaps. Overall, it is reasonably complete for typical use.

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?

Given 0% schema description coverage, the description carries full responsibility for parameter meaning. It thoroughly documents ticker, period, and interval with valid values, defaults, and constraints. However, it references 'start and end' parameters that are not present in the schema, which could confuse an agent. Despite this flaw, it compensates well for the schema's lack of descriptions.

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 'Get historical stock prices for a given ticker symbol' with a specific verb and resource. It lists the data fields returned, distinguishing it from sibling tools like news, statements, recommendations, or overview. The tool's purpose is unambiguous and specific.

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 gives clear context for when to use the tool (when historical stock prices are needed) and provides parameter usage instructions, including valid periods, intervals, and the constraint that intraday data cannot extend beyond 60 days. However, it does not explicitly mention alternatives or when not to use it, so it falls short of a 5.

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