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

Beyond annotations (readOnlyHint=true, etc.), the description details key behaviors: it pulls latest 10-K data from SEC EDGAR/XBRL for companies, handles off-calendar fiscal years, and returns sorted results with citation URIs. No contradiction with annotations.

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 example queries and is well-structured. While it is a bit long, every sentence adds value. Minor redundancy could be trimmed, but overall it is 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?

Despite no output schema, the description explains the return format: paired data + citation URIs and sorted by primary metric. Given the tool's complexity (two entity types, multiple data sources), the description provides sufficient context for an agent to use it correctly.

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?

Schema coverage is 100%, but the description adds valuable context: for company type it lists specific financial metrics (revenue, net income, cash, debt) and for drug type it lists adverse events, FDA approvals, and trial counts. It also clarifies fiscal year handling, which goes beyond the schema.

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 starts with explicit trigger phrases like 'Compare X and Y' and clearly states it performs side-by-side comparison of 2–5 entities. It distinguishes itself from siblings by emphasizing it replaces sequential lookups and providing specific data sources for each type.

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 'ALWAYS PREFER over sequential single-pack lookups when comparing entities,' giving clear when-to-use guidance. It also explains what data each type retrieves, helping the agent choose the right tool and entity type.

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