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

Annotations already indicate readOnlyHint, openWorldHint, idempotentHint, and non-destructive. The description adds substantial behavioral context: data sources (SEC EDGAR/XBRL for companies, FAERS for drugs), handling of off-calendar fiscal years, sorting by primary metric, and return of pipeworx:// citation URIs. This goes well beyond what annotations 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 a single paragraph but well-structured: first listing usage examples, then explaining data sources for each type, sorting, and return format. Every sentence adds value. Could be slightly more structured with bullet points, but is appropriately sized and front-loaded with examples.

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 return format (paired data + citation URIs). It covers two entity types with distinct data sources, fiscal-year handling, and sorting behavior. Minor gap: no mention of pagination or rate limits, but for a read-only comparison tool, this is sufficient.

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% with both parameters described. The description adds meaning by specifying that type='company' pulls revenue, net income, cash, and debt from SEC EDGAR, while type='drug' pulls FAERS adverse-event counts, FDA approvals, and trial counts. It also explains values format (tickers/CIKs for company, names for drug) and constraints (2-5 items).

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 concrete query examples ('Compare X and Y', 'X vs Y', etc.) that immediately clarify the tool's purpose. It specifies side-by-side comparison of 2-5 entities in one call, clearly distinguishing it from sequential lookups. The verb 'compare' and resource 'entities' are explicit.

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.' It provides clear context for when to use this tool (comparison queries) and quantifies the benefit ('Replaces 8-15 sequential lookups'). While there is no explicit 'when not to use', the positive guidance is strong.

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