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

No annotations are provided, so the description carries the full burden of disclosing behavior. It clearly states the tool costs $0.10 USDC per call, is indexed daily from the official listing (no API of its own), and provides a detailed return structure without caveats about strictness or accuracy. This is thorough and upfront about limitations and costs.

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 relatively concise but front-loads the purpose and result structure clearly. The first sentence covers the core functionality; the second adds filtering and update frequency; the third provides pricing and return format. It is well-organized but slightly verbose when describing the nested return fields—could be tighter without losing clarity.

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 moderate schema richness (100% coverage, 6 parameters, no output schema, no annotations), the description is complete enough. It explains the source, pricing, update cadence, and return fields in detail. However, it does not describe pagination or rate limits, and since no output schema is provided, some agents might need more clarity on the exact structure of the returned grants (e.g., format of dates, nested objects). Still, the overview is sufficient for a typical search tool.

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 100%, so the baseline is 3. The description adds value by summarizing the purpose of each parameter in practical terms (e.g., 'Applicant type: individual, business, charity...'), and the enum values for open_now are clearly listed. However, the description does not add nuance beyond what the schema already explains, so a slight bonus is given for clarity but not for adding new semantic depth.

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 clearly states that the tool searches live UK government grants from GOV.UK Find a Grant, listing specific fields returned (name, funder, amount range, dates, etc.) and filtering options. This distinguishes it well from sibling tools like uk_tenders_search, which cover different procurement data.

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 explains when to use the tool (for live UK government grants) and mentions that it is updated daily and provides a machine-readable version since the official source has no API. It does not explicitly exclude competing sibling tools like uk_grants_match or uk_grant_eligibility, but the purpose is clear enough for an agent to infer the correct use case.

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