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

With no annotations supplied, the description carries the full disclosure burden. It does add real behavioral context — the exact data categories returned, the red-flag heuristics applied (NT 10-K, Item 4.02, distress signals), and a per-call price of $0.25 USDC — but says nothing about return shape, latency, failure modes when a ticker is unresolvable, or any auth/rate constraints.

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?

One dense sentence plus an example and a price, with the usage directive front-loaded before the payload inventory. The domain jargon (NT 10-K, Item 4.02) is compact rather than wasteful, though a reader without SEC familiarity gains nothing from the acronyms alone.

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 paid data-retrieval tool with no output schema and no annotations, the description covers what data comes back and what it costs, which is the core need. It still omits the response structure, how cik and ticker interact, and what happens when the lookup fails, which matters for a tool that charges per call.

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 0% and neither parameter is documented, so the description must compensate. The embedded example {ticker:"AAPL"} clarifies the ticker format, but the cik parameter is never mentioned, leaving half the inputs unexplained and the cik-vs-ticker precedence (0 required params) ambiguous.

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 names a specific resource (US SEC due-diligence data) and enumerates exactly what the payload contains: a lite snapshot, six us-gaap companyfacts fields, and red-flag heuristics. The word 'fuller' implicitly positions it against the sibling us_sec, though it never names that sibling outright, so the differentiation is inferred rather than stated.

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?

'Use this for fuller US SEC DD' gives a positive trigger condition, so an agent knows this is the deep-dive option. It never states when NOT to use it (e.g. use us_sec when the cheaper lite snapshot suffices), leaving the cost/coverage tradeoff with the sibling to be guessed.

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