Get Monthly Trend

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

With no annotations, the description itself must convey the operation's behavior; it does indicate this is an aggregated, read-only monthly comparison rather than a transaction-level mutation. It does not clarify edge cases such as whether the current month is included or how month boundaries are calculated.

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 description is one tightly worded sentence that leads with the action and outcome, with no filler or repetition of the parameter schema. Every word contributes to the tool's purpose.

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 simple read-only tool with one optional parameter and an output schema, the description plus schema is largely sufficient for invocation. It is missing only explicit sibling differentiation and boundary caveats, which are useful but not essential to calling it correctly.

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 100% and the months parameter already has a type, default, and description. The description's 'N months' adds little beyond the schema, so the baseline 3 is appropriate.

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 uses a specific verb ('Show') and names a concrete resource ('month-over-month spending totals') with a timeframe, so an agent understands what the tool does. It does not explicitly contrast with siblings such as summarize_expenses or get_category_breakdown, so it only partially earns the top score.

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 is given about when to prefer this tool over alternatives like summarize_expenses or list_expenses, nor does it state any exclusions. The intended use is implied by the name and description, but not explicitly routed.

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