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

Annotations already declare readOnlyHint=true, idempotentHint=true, destructiveHint=false, so the safety profile is covered. The description adds genuinely new context: bills may be inferred from bank history and are flagged with is_inferred=true, saved_plan can be null, and a non-empty upcoming_bills signals bills due in the window. It stops short of describing pagination or failure behavior (e.g., no bank connection).

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 core statement, then the field semantics, then Args and Returns blocks — a clean structure. The dollar-value example sentence is illustrative and earns its place, though the prose is somewhat long for a single-parameter read tool.

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 return-value burden and does so: it lists the returned keys ({as_of, saved_plan | null, upcoming_bills, upcoming_bills_total, scheduled_income_total, checking_available, monitoring}) and explains the meaning of the key nested fields. Combined with the read-only annotations, an agent has everything needed to call and interpret it.

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% (the single 'days' property carries no description), so the description must compensate — and it does, documenting the look-ahead semantics plus the default (14) and max (90) that the schema omits entirely. Only one parameter and no format subtleties keep this from a 5.

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 concrete aggregation: 'The user's standing facts in one call' and enumerates the payload members (saved debt plan resolved to this month, upcoming bills, scheduled income, checking_available, monitoring plan status). An agent knows exactly what this returns. It doesn't explicitly name which sibling it supersedes (get_monitoring_plan, get_cash_flow, get_debt_paydown all overlap thematically), so it falls short of a 5.

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?

Gives explicit triggering questions: 'paying debts, what to pay this month, bills, upcoming money, or spare cash,' plus a concrete example ($252.48 = $202.48 minimum + $50 extra). Clear context for when to reach for it, but no stated exclusions or named alternative tools for when this is the wrong call.

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