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

Annotations already declare readOnlyHint=true, destructiveHint=false, etc. The description adds meaningful behavioral context: matching logic (substring vs exact ABN), accepted ABN formats, and the return structure including totals and per-agency breakdown. It contradicts nothing.

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 three sentences, front-loaded with the core function, then return values, then the question it answers. No redundant information.

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?

Despite having no output schema, the description clearly enumerates the return fields (total AUD, number of awards, first/last dates, per-agency breakdown) and explains the matching modes. It doesn't explain pagination behavior, but the schema covers limit/offset. This is sufficient for an agent to select and invoke correctly.

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 100%, so baseline is 3. The description restates ABN formats and matching modes already present in the schema but does not add new parameter-level meaning beyond the schema. It does help frame the overall purpose, but for individual parameter semantics it doesn't add much.

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 uses a specific verb and resource: 'Every Australian Commonwealth grant awarded to one organisation' and clearly distinguishes from siblings by focusing on recipient matching and aggregation. It names the matching methods (name substring or exact ABN) and the output (funding total, per-agency breakdown), making it distinct from au_grants_search or au_grant_award.

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 the use case by stating it answers 'how much Commonwealth grant money has this charity... received, and from whom.' This gives clear context for when to use the tool. However, it does not explicitly name alternatives or exclusions, so it's not a 5.

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