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

Annotations declare the safe/idempotent read profile, and the description goes well beyond them: it discloses the $1.00/call cost, the MPP/Stripe payment flow, the specific JSON-RPC error -32042 challenge, and the exact retry path via params._meta. That is exactly the operational context an agent cannot get from annotations alone.

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 tight fragments, cost front-loaded before purpose and payment mechanics. Every clause carries information; no filler. Slightly dense but well ordered.

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 explained, and with no input parameters the description's job is mostly operational. It covers cost and the payment handshake; the only real gap is that it never positions this tool against its many siblings.

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 input schema has zero parameters (baseline 4), but the description reveals a required out-of-schema parameter for the payment retry — params._meta['org.paymentauth/credential'] — which the agent would otherwise never discover. That is a genuine semantic addition beyond the schema.

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 concrete verb and output object ('Find evidence-backed supplier and second-order commercial opportunities') and enumerates the evidence sources (SEC EDGAR, EU TED, KAP, infrastructure, price-lag). It is clear what it produces, but it does not distinguish itself from siblings that share those same sources, e.g. shadowgraph_company_filings or shadowgraph_eu_tenders.

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?

There is no stated when-to-use, when-not-to-use, or alternative routing. With nine sibling shadowgraph tools, an agent gets no help deciding between this and shadowgraph_deep_research, shadowgraph_eu_tenders, or shadowgraph_global_brief; usage must be inferred purely from the source list.

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