Budget vs actual

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

Annotations already declare readOnly/idempotent/non-destructive and closed-world, so the safety profile is covered. The description adds genuinely new behavior: the status thresholds (ok / warning at 90%+ / over) and the unit convention (euro cents), which an agent cannot derive from annotations or schema.

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 tight sentences that front-load the resource and grain, then append the status/unit conventions. No filler, though the terse telegraphic style is slightly less scannable than a full sentence.

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 it well: it names the measures and the status vocabulary. Only minor gaps remain, such as whether a default campaign is used and how multiple lines are ordered or aggregated.

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%, with each of farm_id, campaign and group_id documented including defaults and provenance (list_farms, list_groups). The description adds only the crop/category output grouping, not new parameter meaning, 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?

States the resource (budget lines), the grouping grain (campaign x farm x crop x category) and the returned measures (actual spend, remaining, used %, status). This clearly separates it from siblings like finance_dashboard or campaign_forecast, though it never uses an explicit verb such as 'list' or 'retrieve'.

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 statement of when to use this tool versus alternatives such as finance_dashboard, campaign_forecast or group_overview. Usage is only implied by the returned fields; the agent must infer that this tool answers budget-vs-actual questions rather than being told.

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