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

Annotations already declare readOnlyHint=false and destructiveHint=true, but the description adds meaningful context beyond them: it warns this changes the live account and that a confirm:true safety gate must be satisfied. It stops short of describing reversibility or rate/permission constraints.

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 most decision-relevant fact (it is a write to a live account) before the mutation surface and the confirm requirement. 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 five-parameter mutation tool with no output schema, the description covers the write semantics and the confirm gate, which is what an agent most needs before invoking it. It is slightly thin on what the update returns and on how it relates to the status-specific sibling.

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 the schema already documents all five parameters including the confirm gate and the minor-units budget. The description merely echoes name/status/daily budget, adding no syntax or format detail beyond the schema, so the baseline of 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 and resource ('Update a Meta ad set') plus the updatable fields (name, status, daily budget), so the agent knows exactly what is mutated. It does not distinguish itself from the sibling meta_ads_set_status, which plausibly overlaps on the status field, so sibling differentiation is incomplete.

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 gives a hard precondition ('Requires confirm:true') and flags that this is a live-account write, which is real usage guidance. It never says when to choose this over meta_ads_set_status or meta_ads_update_campaign, so the alternative-selection guidance is only implied.

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