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

Annotations already declare readOnlyHint, idempotentHint, openWorldHint, and destructiveHint=false, so the safety profile is fully covered. The description contributes little beyond that, though 'official' and 'kurs transaksi' do tell the agent the data is authoritative BI-published transaction rates rather than market quotes. It says nothing about freshness or update cadence, which is the most relevant behavior for a 'latest' endpoint.

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?

One short sentence, front-loaded with the verb and data source, with no filler. Slightly duplicative of the title ('Latest Bank Indonesia rates'), which costs it a point.

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 (one optional parameter, no nesting) and annotations cover safety, but there is no output schema, so the description should say at minimum what a result contains (rate values, currency pairs, effective date). Without that, the agent knows what the tool fetches but not what it returns.

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% and the single parameter's description already specifies comma-separated ISO codes and the USD,EUR,SGD default. The description repeats the same three codes, adding no syntax or constraint information beyond the schema, so the baseline of 3 applies.

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 states a specific verb and resource: 'Get latest Bank Indonesia (BI) official exchange rates', and adds the local term 'kurs transaksi' clarifying which BI rate table is used. It does not name the sibling tools it differs from, but the word 'latest' combined with 'BI' implicitly separates it from kurs_bi_history and kurs_latest.

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 only implied: 'latest' signals the current-rate use case versus history, but the description never says when to pick this over kurs_latest, kurs_history, or kurs_bi_history, nor does it state any prerequisite or freshness caveat.

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