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

Annotations already cover the safety profile (readOnly, idempotent, openWorld, non-destructive), so the bar is lower, and the description adds genuinely non-obvious behavior: it is a paid tool at $1.00/call and payment is handled via HTTP 402 / MPP. What is missing is anything about rate limits, quota, or what the paid call actually returns in breadth.

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?

Three short sentences with the cost front-loaded, then capability, then payment mechanics. No filler or restated naming; every clause carries information an agent needs before calling.

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?

An output schema exists, so return values need not be described, and the payment/authentication path is disclosed. The one real gap is competitive positioning against the seven sibling tools, which for a zero-parameter paid tool is the main thing an agent still has to infer.

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?

The tool takes zero parameters, so per the baseline there is nothing for the description to disambiguate; the empty schema plus 100% coverage means no gap exists. No swarm or scope options are mentioned, which is consistent with the schema but leaves no room for upside.

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 gives a specific verb ("Find") and a concrete resource ("supplier and second-order commercial opportunities") plus named evidence sources (SEC EDGAR, EU TED, KAP, price-lag). It does not, however, differentiate itself from close siblings such as shadowgraph_opportunity or shadowgraph_market_signal, so an agent cannot choose between them from the text 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?

Usage is only implied by the capability statement; there is no explicit when-to-use or when-not-to-use guidance and no pointer to a free alternative (shadowgraph_free_preview exists as a sibling). The cost disclosure ($1.00/call) is useful decision input but is not routing guidance.

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