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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, so the safety profile is covered. The description adds useful context about month-over-month scoping and output behavior (accounts increasing/decreasing), but it does not disclose edge cases such as default fiscal_year handling or whether comparisons include prior-year 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?

Two short sentences front-load the action and scope, then state the output. No filler or redundancy; every word adds value.

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?

For a read-only trend tool with fully documented parameters and safety annotations, the description adequately explains purpose and return behavior. It lacks detail on optional parameters' defaults (fiscal_year, account_type) and doesn't help differentiate from closely related financial tools, but these are minor for a tool of this complexity.

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 all three parameters (companyId, fiscal_year, account_type) are already documented. The description mentions financial trends but adds no meaning to the parameters beyond what the schema provides, so the baseline 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 action and resource: 'Get month-over-month financial trends' and specifies the analytical output ('Shows which accounts are increasing/decreasing'). It is distinguishable from siblings like get_financial_summary or get_actuals_vs_budget by its trend focus, though it doesn't explicitly name any sibling.

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 implies usage for financial trend analysis but provides no explicit when-to-use or when-not-to-use guidance, nor does it name alternative tools. An agent with ambiguous requests like 'compare this year's spending' would have to infer whether this tool or get_actuals_vs_budget is more appropriate.

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