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

Annotations already declare read-only and idempotent, so the safety profile is covered. The description adds useful behavioral context: the default sort order, the ability to get all deposits with no filters, and troubleshooting advice for empty period results. This goes beyond the annotations without contradicting them.

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 purpose, followed by practical usage notes. Every sentence contributes meaningful information without fluff 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?

With no output schema, the description should clarify what the returned data looks like. It only says 'returns interest rates by amount and period,' which is vague and somewhat inconsistent with the schema (no 'amount' parameter exists). It doesn't mention that results include bank names or deposit product specifics, which would be expected from the filterable fields. This leaves some ambiguity for the agent.

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%, with all six parameters fully documented (e.g., allowed values, defaults, examples). The tool description adds no additional parameter-level information, so the baseline score of 3 is appropriate.

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 searches and compares bank deposits (lokaty) in Poland, and specifies that it returns interest rates. This distinguishes it from sibling tools like SearchSavingsAccounts and GetBanks, which handle other account types or banks. The verb 'search and compare' is specific and matches the tool's name and behavior.

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?

Provides clear usage context: call with no filters to get all deposits sorted by rate, and suggests fallback strategies for empty results (remove period filter or try adjacent periods). However, it does not explicitly mention when to use this tool over sibling alternatives (e.g., SearchSavingsAccounts), so it stops short of a 5.

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