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

Annotations already declare readOnlyHint, idempotentHint and non-destructive, so the safety profile is covered. The description usefully adds unit and date conventions, but omits behavior for the optional period argument (what happens when it is omitted) and any error/edge behavior.

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-loads what the tool returns, then follows with the two format conventions an agent needs. Compact and free of filler, though the units/dates sentence is dense enough that it could be split 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?

With no output schema, the description carries the burden of describing the return shape and does so reasonably (plan, spent, average, pace, expenses, income). The remaining gap is the undefined fallback when period is omitted.

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%, so the description must compensate. It does explain the period format well ('a month is a budget period YYYY-MM, the one that starts in that month') and the minor-unit convention, but leaves the default behavior for the optional period unspecified.

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 the resource and its contents concretely: a budget month's per-category plan with spent amounts, a 12-month average and pace, plus expenses and income. Clear what the tool returns, but it never distinguishes itself from close siblings like get_overview, get_analytics or get_goal_plan.

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 when-to-use guidance and no alternative named. An agent cannot tell from the description when to call get_budget versus get_overview or get_analytics, nor when a non-current period is appropriate.

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