Get TCMB exchange rates

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

Annotations already declare readOnlyHint, openWorldHint and idempotentHint, so the safety profile is covered. The description adds real behavioral context beyond the schema: the data is the official TCMB bulletin, and omission of parameters yields the latest bulletin / all ~22 currencies. It stops short of saying what happens for non-publication days (weekends/holidays), which is the one behavior an agent would still want.

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?

Two tight sentences, zero filler, with the resource and unit front-loaded before the default-behavior clause. Every clause earns its place.

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 an output schema present, return values need no explanation, and annotations cover the safety profile, so the description only needs to cover purpose, defaults, and units — which it does. The remaining gap is edge-case behavior for dates with no published bulletin.

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 50% (the `currencies` array itself has no top-level description). The description compensates by defining the return unit (TRY per foreign currency), the default cardinality (~22 currencies), and the meaning of an omitted `date` (latest bulletin) — meaning that the schema does not carry.

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 resource (TCMB official exchange rates) with the semantic unit defined (TRY per unit of foreign currency) and the temporal scope (for a date). It is clearly distinct from convert_currency and get_rate_history by being a single-date official-bulletin lookup, though it never names those siblings explicitly.

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 tells the agent how to use the parameters (omit `date` for latest, omit `currencies` for all) but gives no guidance on when to choose this tool over get_rate_history or convert_currency. Usage is implied by the 'for a date' framing rather than stated.

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