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

Annotations already declare readOnlyHint and openWorldHint, but the description adds a genuinely non-obvious trait: it is a paid x402 endpoint costing $0.004 USDC per call. That is exactly the kind of cost/call-budget information an agent needs before invoking, though rate limits or failure behavior are unstated.

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?

Two sentences, front-loaded with resource and country scope, then filters, then cost. Dense and largely waste-free, though the 'eligibility' clause is dead weight since no such parameter exists.

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 usefully enumerates returned fields (agency, number, open/close dates, apply link) and discloses the per-call cost. Gaps remain around what limit does and what status values change, but the core contract is covered.

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 only 25% (only 'status' documented), so the description must carry more weight. It loosely covers q ('matching your keywords') and agency ('Filter by agency'), but never explains limit or status behavior, and mentions an 'eligibility' filter that has no parameter.

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 verb+resource and scope: US federal grant opportunities from Grants.gov, open and forecasted, keyword-matched. No sibling tool covers grants, and the 'open and forecasted' qualifier makes the scope unambiguous.

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?

It indicates how to narrow results ('matching your keywords', 'Filter by agency or eligibility'), which is usable context, but gives no when-to-use/when-not guidance or alternatives. It also references an 'eligibility' filter that does not exist as a parameter, which muddies the guidance.

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