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

Annotations already declare readOnly/idempotent/closed-world, and the description adds real context beyond them: data has a date and source that must be surfaced, attribution to "Isoba (LOKIO)" is required, and the reading must be framed as historical base rates rather than a forecast or signal. Those are genuine usage constraints the schema and annotations do not carry. What is missing is any note on freshness, coverage, or latency of the underlying data.

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 content is dense and front-loaded with the return payload, so the first clause orients the reader quickly. But it is one sprawling paragraph with stacked parentheticals ("for USD — what 1 euro costs", "for cash — the next year") and a long tail of editorial instructions that could be split into distinct sentences for scanability.

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?

No output schema exists, so the description must carry the return shape — and it does, covering price, date, source, monthly/annual change, similar-past-moment statistics (case counts, typical outcome, deciles, best/worst), holder risk, and the currency-specific "wait a week?" figure. For a one-parameter read tool, an agent can call it and interpret the result without further information.

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?

The single currency parameter is fully documented in the schema down to the ISO 4217 pattern and USD default, and the description reinforces the one-currency scope with its USD/EUR explanation. It adds no new semantics such as which currencies are actually supported or how a bad code is handled, so it lands at the baseline for full schema coverage.

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 names the specific resource — the "Your money" card for a single currency — and enumerates exactly what comes back (FX rate, gold, Brent, bitcoin, cash/inflation, plus change and historical-case stats). That is far more concrete than the title alone. It does not, however, distinguish itself from siblings such as get_current_readings or get_monthly_history, which cover overlapping subjects, so an agent still has to infer the split.

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?

There is no statement of when to pick this over get_current_readings, get_expectations, or get_monthly_history; selection must be inferred from the payload description. What guidance exists is about how to frame the output (history not forecast, no buy/sell advice, flag when a user asks for personal advice), which is presentational rather than tool-selection guidance.

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