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

Annotations already declare readOnly, idempotent, non-destructive, openWorld, so the safety profile is covered. The description adds real behavioral context beyond that: the default 3-year window when no dates are given, and the ranking rule (absolute total). It doesn't mention pagination or granularity limits, so a 4 rather than 5.

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?

Front-loaded with the report identity and output shape, then defaults, then the routing sentence. Every line earns its place with zero filler.

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?

An output schema exists, so return values need not be described, and annotations cover the safety profile. The description is nearly complete; the only gap is the undocumented portfolio and property_ids parameters.

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 0% across 5 parameters, so the description must carry the load. It clarifies date behavior (defaults to a 3-year window) and implies top_n via 'ranked by absolute total', but leaves portfolio, property_ids, top_n semantics, and date format entirely unexplained.

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 verb+resource ('Multi-year P&L by account'), names the underlying report (ProfitLossRecapYear, report 201), and describes the output shape (year-matrix per account ranked by absolute total). It clearly distinguishes itself from the two nearest siblings by naming them.

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?

Explicitly routes the agent: 'For year-over-year deltas use analyze_pl_yoy; for monthly trajectory use analyze_pl_trend', and provides sample questions ('how has revenue moved across 3 years') that anchor when to reach for this tool. Nothing is left to inference.

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