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

The description explains that criteria are parsed once at ingest and not guessed at request time, and that if not fully parsed, it uses Find a Grant's listing fields with PARTIAL_CRITERIA flag. It also mentions cost and what returns. Annotations are not provided, so the description carries the full burden and does it well, though it could mention if the call is read-only or has side effects.

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 dense with information but slightly long due to the detailed output structure. It is front-loaded with the tool's core purpose and key behaviors. Could be slightly more concise by trimming the output example, but every sentence serves a purpose.

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 tool's complexity (4 parameters, nested objects, cost, and eligibility logic), the description covers purpose, input semantics, behavioral caveats, and cost. With no output schema, it details return values. It misses explicit guidance on error handling or prerequisites (e.g., grant must exist), but is largely complete.

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 already covers all parameters with descriptions (100% coverage), but the description adds value by explaining how 'declare' works ('a first call tells you what to declare on the second') and that 'id' is the Find a Grant slug or alias. It enhances understanding beyond the schema without redundancy.

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 the tool provides a deterministic eligibility verdict for one grant and one project, with specific outputs like a full criteria table, missing information, and indicative funding. It distinguishes itself from siblings by focusing on grant eligibility rather than company profiles or tender scoring.

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 implies use for determining grant eligibility with a single grant and project, and notes that it costs $0.15 per call, which guides cost-conscious usage. However, it does not explicitly indicate when to use this tool versus alternatives like uk_grants_match or uk_tenders_fit_score, though the focus on eligibility is clear enough.

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