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

Beyond the readOnly and idempotent hints, the description details data sources (SEC EDGAR/XBRL, FAERS), behavior (off-calendar fiscal years handled, results sorted by primary metric), and output format (paired data + citation URIs). This adds substantial behavioral context beyond 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 dense but every sentence serves a purpose: examples, usage rule, type-specific details, sorting behavior, and output. It's long but appropriately structured for a tool with two entity types and multiple data sources. No fluff.

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 tool with no output schema, the description fully covers what the agent needs to know: input limits, type-specific data points, sorting, and return format with citation URIs. It also explains why it's better than alternatives, making it self-contained.

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 covers both parameters at 100%, but description adds meaning by explaining what each 'type' returns and gives examples for 'values' (tickers/CIKs vs drug names). It also clarifies the parallel nature and the limit of 2–5, reinforcing schema constraints with practical context.

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 the tool's purpose: side-by-side comparison of 2–5 companies or drugs in one parallel call. It provides specific example queries ('Compare X and Y', 'rank these companies') and explicitly distinguishes from sequential single-entity lookups, unlike sibling tools like entity_profile.

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?

It gives explicit guidance: 'ALWAYS PREFER over sequential single-pack lookups when comparing entities' and mentions it replaces 8–15 lookups. It does not name specific sibling tools but provides clear when-to-use context. Missing explicit 'not for single entities' but that's implied.

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