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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive). The description adds real behavioral context beyond them: it explains the fallback to an older 10-K and the 'latest_annual_filing'/'note' fields that signal staleness, plus the business_screen caveat where purification does not apply.

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 content is front-loaded with the core purpose, then returns, then the edge-case caveat. It is dense but each clause carries information; only the nested parenthetical about 'latest_annual_filing' is slightly heavy.

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 burden of explaining return values, which it does (ratio, charity amount, stale-filing fields, business_screen message). Complete enough to call correctly, though it omits error cases such as a ticker with no qualifying filing.

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%, so the baseline is 3, but the description adds meaning beyond the schema: it clarifies that 'dividend' is optional and, when supplied, produces a charity amount, and it distinguishes the returned ratio semantics from the input.

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 computation (purification ratio = interest income over total revenue) and an optional derived output (charity amount for a given dividend). This clearly separates it from siblings like screen_company and calculate_zakat.

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 implies usage by explaining inputs and outputs, but never states when to reach for this tool versus screen_company or calculate_zakat. No explicit prerequisites or exclusions are given.

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