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

Annotations already declare readOnly/openWorld/idempotent/non-destructive, so the safety profile is covered. The description adds genuinely useful behavior beyond that: the data provenance (SEC 10-K with accession number and exact page) and the fallback behavior when the marketer is private, foreign, or unlisted ('it says so and names them rather than returning nothing').

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?

Front-loads the core purpose in the opening clause before expanding into the resolution mechanics. Four dense sentences with no filler, though the middle sentence on the FDA/SEC join is somewhat verbose relative to its instructional value.

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?

With no output schema, the description carries the return-shape burden and does so fully: sales by period and region, plus provenance identifiers. It also closes the obvious edge case (private/foreign/unlisted marketers), leaving nothing an agent needs to call this 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 description coverage is 100%, so all three parameters are already documented in the schema. The description adds conceptual context (brand names, marketer resolution, the join problem) but no syntax or format detail beyond what the schema provides, so baseline 3 is correct.

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?

States a specific verb and resource ('how much revenue a specific DRUG generates for the company that sells it') and nails the output shape (sales by period and region, with accession number and filing page). It never names a sibling like pharma_sales_at_risk or pharma_drug_profile to differentiate itself, so an agent must infer the boundary from phrasing alone.

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?

Gives a clear invocation path ('ask by brand name') and explains when the optional company parameter is warranted versus letting resolution run. It provides no explicit when-not or alternative-tool guidance, so the routing versus pharma_sales_at_risk is left implicit.

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