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

No annotations are provided, so the description carries the burden. It does disclose meaningful behavioral context: the currency (euros), the data source ('saved snapshots', implying cached/stored rather than live), and the exact metrics returned. It does not state freshness/lag, auth requirements, or whether snapshots must pre-exist.

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?

A single, front-loaded sentence that names the subject first and enumerates the timeframes compactly. No wasted words.

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 no output schema and no parameters, the description must convey the return shape, and it does reasonably well: total plus change across four windows in euros, sourced from snapshots. Missing only data-freshness/lag detail, which is a minor gap for a parameterless read tool.

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?

Zero parameters, so the baseline is 4. There is nothing for the description to disambiguate at the argument level.

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 (portfolio performance/PnL) with concrete scope: current total and change over 24h/7d/30d/since start. An agent can tell it apart from get_portfolio (holdings) or get_realized_gains (tax-relevant gains). It lacks an explicit verb but the resource+metric is unambiguous.

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?

No guidance on when to use this versus siblings like get_portfolio, get_portfolio_score, or get_realized_gains. No prerequisites or exclusions stated; the agent must infer that this is the performance-over-time view.

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