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

Annotations already declare readOnlyHint, idempotentHint, openWorldHint and destructiveHint=false, so the safety profile is fully covered structurally. The description adds almost nothing beyond that — notably it does not say what is returned when CBO is disabled (null budget? flag false?), which is the key behavioral ambiguity for this tool.

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 sentences, front-loaded with the question the tool answers. There is mild redundancy — the first line and the 'Check if CBO... is enabled' clause restate the same idea with the acronym expansion inserted between them.

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?

A simple two-required-parameter read tool with no output schema, so the description should at least sketch the return shape (CBO flag plus budget fields) and the disabled case. It covers the intent but leaves the response contract entirely to inference.

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%: campaign_id is documented as 'Campaign ID to check' and ad_account_id includes its act_ prefix pattern and a pointer to list_ad_accounts. The description adds no further meaning beyond the schema, 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 a specific resource and outcome: whether a campaign uses Campaign Budget Optimization and what that budget is, plus the verb 'check/get'. It is distinguishable from list_campaigns or get_campaigns by its budget-strategy focus, though it never names those siblings to sharpen the contrast.

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?

'Use to understand budget strategy' implies a context but gives no explicit when-to-use boundary, no when-not, and no alternative tool named. An agent knows the general situation but must infer when this is preferred over fetching the campaign itself.

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