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

Annotations only cover the safety profile (readOnly, idempotent, non-destructive, open world); the description goes well beyond them by disclosing carry-over semantics, the effectiveDate/carriedOver fields and when to quote them, the error on unpublished dates, the Tbilisi calendar basis, and the one-request-per-call limit. This is exactly the behavioral context an agent needs to interpret results correctly.

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?

Purpose and scope are front-loaded in sentence one, and every sentence carries information (carry-over, errors, summary, request budget). The middle section is a dense run-on that takes effort to parse, but there is no filler to cut.

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?

For a 3-parameter, single-request range query with an output schema, the description covers the edge cases that matter: carry-over days, unpublished-date errors, and the server-computed summary. Even though an output schema exists, the explanation of carriedOver semantics is the key to correct interpretation and is fully provided.

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 baseline is 3; the description adds genuine meaning beyond the schema by fixing the unit (GEL per one unit) and the timezone basis (Tbilisi calendar days), neither of which appears in the parameter descriptions. It restates the 366-day cap rather than adding to it.

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 first sentence names a specific resource (official NBG rate), its unit basis (GEL per one unit), and its exact scope (every calendar day of an inclusive range up to 366 days). That scope is clearly distinguishable from the convert and list_currencies siblings, which serve different jobs.

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?

Usage is implied by the range-based framing, but no sibling is named and there is no explicit statement of when to prefer this over nbg_get_rates or nbg_convert. The closest thing to guidance is operational ('one NBG request per call', 'report summary rather than deriving them'), which governs use of the result rather than tool selection.

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