Google 広告の日予算を変更

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

Annotations already declare write (readOnlyHint=false), non-destructive, open-world. The description adds genuinely useful behavioral context beyond that: the amount is expressed in whole currency units, not micros, which is a real trap in the Google Ads API. It doesn't cover reversibility, rate limits, or propagation delay.

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?

Three short sentences, front-loaded with the action and the single most important pitfall (budget resource vs campaign), then the id source, then unit semantics. No 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?

For a mutation tool with no output schema and full annotation coverage of the safety profile, the description supplies the two things an agent most needs: the correct id source and the unit convention. Minor gaps remain around side effects and confirmation of what the call returns.

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%, so both budget_id and daily_amount are already documented, including the 'not a campaign ID' warning and the currency-unit note. The description reinforces but does not add meaning beyond the schema, so 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 a specific verb (日予算を変える = change daily budget) and resource, and explicitly distinguishes the target from the near-miss sibling concept by stressing the destination is the budget resource, not the campaign. An agent can route between this, google_ads_create_budget, and google_ads_update_status without opening schemas.

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?

It tells the agent where to obtain the required id (google_ads_list_objects returns campaignBudget.id), which is concrete usage context. It does not state exclusions or when to prefer google_ads_mutate instead, so it stops short of full routing guidance.

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