Overview — Budget snapshot

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

Annotations already declare readOnlyHint=true, openWorldHint=false, destructiveHint=false, so the safety profile is covered. The description adds real behavioral context beyond that: it is a 'single-call' aggregate and, crucially, 'Costs three requests,' a cost disclosure an agent needs before invoking. This is the kind of non-obvious trait the description should carry.

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 '[READ] Single-call budget health snapshot' lead, then outputs, then unique fields, then cost. Every sentence earns its place, including the cost note, with no redundancy or 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 needn't be explained in prose, and annotations cover the safety profile; the description still adds selection value by naming the aggregate contents and the unique fields. The only material gap is the unexplained plan_id, which keeps it from a full 5.

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?

The single parameter plan_id has 0% schema description coverage and is not mentioned anywhere in the description. With low coverage the description must compensate for the ambiguity (what plan_id means, whether it defaults to a primary plan), and it does not; the agent must infer behavior from the nullable default alone.

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 ('single-call budget health snapshot') and enumerates the concrete outputs (income, spending, to-be-budgeted, age of money, overspent categories), which lets an agent predict the payload. It also flags value nothing else surfaces (unfunded_card_debt, trapped_funds), aiding disambiguation. It stops short of naming which sibling overview_* tool it replaces, so it's clear but not fully differentiated.

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?

'Good first call for any budget session' gives explicit positive context for when to reach for it. It does not, however, name alternatives (overview_month_health, overview_balance_identity, overview_cash_position) or state when-not to use it, so an agent can't fully route between the sibling overview tools.

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