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

The readOnlyHint and openWorldHint annotations already signal a safe read operation. The description adds useful behavior beyond that: it reveals that results are canonical security identities, capped at 10, with CUSIP/ticker/issuer/sector/listing status, and instructs verification against source_url fields. It could go further by disclosing empty-result behavior or fuzzy match handling, but the provided context is adequate.

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 with clear labels: WHEN TO USE, WHEN NOT TO USE, RETURNS, and VERIFICATION. Each sentence adds actionable information, and the core purpose statement is front-loaded.

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 this is a read-only search tool with two simple parameters and an output schema, the description is complete: it explains when to call it, when not to call it, what values go in, what comes back, and how to cite results. No critical information is missing for an agent selecting and invoking the tool.

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?

With schema description coverage at 0%, the description compensates by defining the query parameter as a ticker or company name and by explaining that limit caps matching securities at 10. It does not explain every nuance of query matching or confirm even partial matching, but it gives enough for an agent to invoke the tool correctly in ordinary cases.

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 and resource: 'Searches stocks by ticker or company name and returns canonical security identities.' It clearly distinguishes the tool from siblings by emphasizing canonical CUSIP resolution. The WHEN NOT TO USE section even names analyze_stock and find_signals as alternatives, so a selecting agent loses no ambiguity.

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 explicitly states WHEN TO USE and WHEN NOT TO USE, naming concrete alternatives: analyze_stock for an ordinary ticker/CUSIP and find_signals for screening across stocks. This leaves little or no room for an agent to choose the wrong tool.

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