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

With no annotations present, the description carries the full behavioral burden. It discloses a non-obvious transactional behavior: the tool returns checkout details, and results are only available after payment through a separate call. It could go further by explaining what ni_order_status returns, but the core workflow is transparent.

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?

The description is two sentences with no fluff: the first states the primary purpose, and the second captures the required follow-up workflow. Every clause contributes actionable information, and key price and next-step details are front-loaded logically.

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?

Given the absence of an output schema and annotations, the description covers the essential calling contract: returns checkout_url and order_id, and tells the agent to call ni_order_status afterward. It doesn't describe failure modes or the exact format of final results, but the workflow is sufficiently complete for correct invocation.

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 coverage is 50%: discipline is described in the schema, but tier is only an enum/default with no explanation. The description adds meaning to tier by mapping 'standard' and 'agentic' to prices, but it does not explain the substantive difference between the tiers, leaving some semantic ambiguity.

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 states a specific action ('Search open grant opportunities'), a clear scope ('for a discipline'), and the outcome ('matched listings'), so an agent knows exactly what this tool is for. It further distills the paid workflow by naming the tier options, making it distinct from generic search tools among the siblings.

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 clear context for when to use the tool: to search grant opportunities and obtain a checkout_url and order_id. It also points to the next step, calling ni_order_status after payment, which provides routing guidance, though it does not explicitly contrast this tool with other search-like siblings such as ni_store_search.

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