update_budget

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

Annotations already declare readOnlyHint=false, idempotentHint=true, and destructiveHint=false, covering the core behavioral safety profile. The description adds that it updates an existing budget, but it does not disclose update semantics such as whether omitted optional fields preserve their current values, what the return value is, or how failures are reported.

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 a single clear purpose line followed by a tight argument list. There is no fluff, every parameter gets exactly one explanatory line, and the structure is easy to scan. The form is appropriate for a tool with five parameters.

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?

The description adequately supports a basic invocation by explaining all parameters, but it leaves gaps: it does not state whether updating one field preserves others (partial update semantics), what the tool returns, or what happens if the budget doesn't exist. Since there is no output schema, the description would need to mention the response for full completeness.

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 0%, so the description carries the full burden of explaining parameters. It does this well by describing every parameter: customer_id as a Google Ads customer ID, budget_id as the budget to update, amount as a daily budget amount 'in currency', and delivery_method with its allowed values 'STANDARD' or 'ACCELERATED'. It could be more precise about units (e.g., micros vs major units) and the effect of omitting optional fields, but the parameter documentation is substantially better than the empty schema.

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 'Update' and a specific resource 'existing campaign budget', which clearly distinguishes it from siblings like create_budget, list_budgets, and get_budget_utilization. The word 'existing' further clarifies that this tool operates on an already-created budget rather than creating a new one.

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?

The description clearly establishes the context: use this tool when you need to modify an existing campaign budget. This is enough to route an agent away from create_budget and list_budgets, but it does not explicitly name alternatives or state when not to use the tool, so it falls just short of full explicit guidance.

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