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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, covering the safety profile. The description adds that it performs a comparison, which is a mild behavioral trait, but it does not disclose the nature of the output (e.g., difference, recommendation) or any computational side effects. With annotations covering safety, this is adequate but not rich.

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 a single, focused sentence with no filler. It front-loads the core action ('Compare') and includes the key objects and scope. Every word earns its place; it is an exemplar of conciseness.

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?

The tool is simple (2 params, read-only), and an output schema exists, so return-value documentation is not required. However, the description omits any usage context or differentiation from siblings, and it does not explain what 'current top savings APY' means (e.g., is it the highest across all banks or within a specific category?). For a low-complexity tool this is barely adequate, but it leaves some ambiguity that could affect 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 description coverage is 0%, so the description must compensate for parameter meaning. The description references 'user's current APY' (currentApy) and 'a balance' (balance), providing basic identification, but it does not clarify units (e.g., APY as percentage, balance as dollars), constraints beyond schema ranges, or how these parameters influence the comparison. Given the low coverage, this is a meaningful gap.

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 ('Compare') and names both the resource ('user's current APY') and the reference ('SwitchWize's current top savings APY'), with the balance parameter mentioned as the scope. It clearly distinguishes from siblings like get_top_rates (which likely just returns top rates) and get_bank_gap (which might compute a gap). No ambiguity remains about the tool's function.

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 provides no guidance on when to use this tool versus the 14 siblings. It does not mention alternatives, prerequisites, or conditions that would select this tool over, for example, get_top_hysa_rates or best_move_this_week. The context implies it is for comparing a user's rate to the top rate, but no explicit routing is given.

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