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

With no annotations, the description carries the full burden and does disclose two non-obvious behaviors: the overloaded fallback response (profiles list when profile is omitted) and the rule that unknown line items are never counted as 0 €, guarding against silent underestimation. It omits currency, whether results are point estimates or ranges, and read-only/rate-limit context.

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?

Three short sentences, front-loaded with the core purpose, followed by the fallback rule and the estimation caveat. No filler or repetition.

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?

Adequate for a two-parameter read tool, but with no output schema the description never says what the returned costs look like (per-bank totals, breakdown by fee category, currency, ranges), which is the main thing an agent needs to interpret the response.

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 the schema already documents both parameters and even enumerates example profile IDs. The description only restates that banks are 'several' and that the profile must be explicit; the useful profile-omission behavior is behavioral rather than parameter-level detail.

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?

States a specific verb+resource: estimated annual cost for several banks given an explicit usage profile, which distinguishes it from the sibling compare_banks (generic comparison) by the cost/profile framing. It does not explicitly name the alternative, so it stops short of 5.

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?

Gives concrete usage context: a profile is required for meaningful results, and if none is supplied the tool instead returns the list of available profiles. It does not explicitly route the agent to siblings like get_bank_fees or get_fees_barometer for raw fee data, so no exclusion guidance.

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