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

Adds substantive behavior beyond annotations: it is a paid tool ($0.01/call), payment settles in USDC on Solana via x402, and the MCP flow requires a first unauthenticated call to obtain a PaymentRequired challenge before retrying. Annotations only declare openWorldHint/idempotent/readOnly flags and say nothing about cost or the two-step payment handshake.

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 front-loaded sentences: purpose first, then price, then the invocation mechanics. The payment paragraph is dense but every clause is operationally necessary for a paid endpoint; nothing is padding.

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?

No output schema and no mention of return shape, default/maximum limit, or pagination semantics for limit/offset — gaps an agent must guess at for a 17-param list tool. The payment and endpoint details are complete, but the result-side and filter-value information is thin.

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?

17 parameters whose schema 'descriptions' are bare type names ('integer', 'number', 'string'), so nominal 100% coverage carries almost no semantics. The description's only compensation is 'Finviz-style filters', which hints at familiar field meanings but omits units (market_cap scale), allowed values for sector/industry/country, and valid sort_by/sort_dir tokens (no enums provided).

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?

Specific verb+resource: 'Screen the S&P 500 with Finviz-style filters' clearly states what the tool returns (a filtered list of large-cap US equities). It implicitly distinguishes itself from screener_quote by emphasizing multi-constraint filtering, though it never names that sibling explicitly.

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 gives detailed invocation guidance (payment challenge/retry loop), but no guidance on when to choose this over screener_quote or other finance tools, nor on what filter combinations are sensible. Usage context is implied by the filter vocabulary rather than stated.

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