Stock quote (EOD)

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

Beyond the readOnlyHint annotation, the description discloses the EOD-frozen nature of the data and details the special case where an uncached symbol during market hours returns only identity plus previous_close with null fields and stale=true. This is substantial additional behavioral context that the annotation alone does not provide.

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 compact yet covers the core function, included fields, and a critical caching caveat in a single well-organized paragraph. Every sentence adds actionable information without filler or redundant repetition of the schema.

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 description fully covers the tool's behavior, including the edge-case stale response and a pointer to the meta field in the output schema. Since an output schema exists, return values are documented, and the description complements it with usage-level detail.

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 schema's symbol parameter has no description (schema description coverage 0%), but the tool description specifies it is a PSE stock symbol and gives valid examples (SM, AREIT, BDO). This compensates for the missing schema description and gives the agent concrete formatting guidance.

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 opens with a specific verb phrase 'Get the latest end-of-day quote for a PSE stock symbol' and includes concrete examples (SM, AREIT, BDO). This clearly distinguishes it from siblings like get_price_history by focusing on the latest EOD snapshot rather than historical time series.

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 obtaining current EOD quotes but does not explicitly discuss when to prefer this tool over alternatives like get_price_history. No exclusions or when-not-to-use guidance is provided, leaving the agent to infer the appropriate context from the sibling names.

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