frankfurter_timeseries

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

Annotations declare readOnlyHint, destructiveHint, openWorldHint. The description adds important behavioral context beyond annotations: 'Daily reference rates, not real-time', 'Only business days included (weekends/holidays omitted)', 'Requires symbols filter to control response size'. No contradiction.

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 concise sentences. The first sentence states the core purpose and primary constraint (max 90 days). Every sentence adds value with no redundant wording.

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?

Without an output schema, the description could explain return format, but 'Get daily ECB forex rate history' and 'Use for currency trend analysis' imply the output is a list of historical rates. The description covers parameter usage and data nature, making it sufficiently complete for agent usage.

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%, so baseline is 3. The description only repeats that symbols is required and max 90 days is a constraint, adding minimal new semantic value beyond the schema's parameter descriptions.

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 it gets 'daily ECB forex rate history for a date range (max 90 days)', specifies 'Daily reference rates, not real-time', and is 'Use for currency trend analysis'. This distinguishes it from siblings like frankfurter_latest (single latest) and frankfurter_convert.

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 gives clear context for use ('currency trend analysis') and hints at when not to use ('not real-time'), but does not explicitly name alternatives or state when not to use. It mentions the required symbols filter and max 90 days, which helps the agent decide.

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