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

Adds substantial behavior beyond the annotations: effect latency ('takes effect within minutes'), replacement semantics with no history at this layer, positivity validation, and a spend-cap risk warning. Even with destructive/idempotent hints already present, this meaningfully deepens the agent's understanding of consequences.

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 short paragraphs, front-loaded with what the tool does and its immediate effect, followed by validation and confirmation guidance. Every sentence carries a distinct, useful fact with no redundancy.

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?

For a destructive mutation with no output schema, the description covers effect timing, overwrite behavior, input validation, and the confirmation workflow, while annotations carry the safety profile. Nothing an agent needs to call this correctly is missing.

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 100%, so the schema already documents all three parameters, including the positive-budget constraint (exclusiveMinimum: 0) and the confirm flag. The description reinforces the positive-validation rule but adds no syntax or format details beyond the schema, so baseline 3 is appropriate.

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 and resource ('Update the daily budget of a live Google Ads campaign') and scopes it to a 'live' campaign, which implicitly distinguishes it from draft-oriented siblings like edit_campaign_draft and generate_campaign_draft. An agent can identify the operation without opening the schema.

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 a clear cautionary guideline ('Strongly recommend confirming with the user before calling') and ties it to the risk of overspending, which shapes how the tool should be invoked. However, it never names when to use this versus alternative budget-adjustment paths or siblings, leaving the routing guidance implied rather than explicit.

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