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

Annotations already declare readOnlyHint=false, destructiveHint=false, and openWorldHint=false, so the description's job is lighter. It still adds real context the annotations lack: an approval draft is written, approval_ref and plan_digest are returned, delivery is unchanged, and a separate confirm tool must be called. It does not describe draft lifecycle details such as expiry or whether re-preparing overwrites a pending draft.

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?

Four compact sentences, front-loaded with the action and the return contract, then the confirmation requirement and the alternative. Nothing is repeated from the annotations or schema, and every clause carries operational weight.

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 tool has an output schema, so return values need not be spelled out in depth, yet the description still names the key outputs and the approval gating. For a three-parameter prepare tool this is nearly complete; the only material gap is that the parameters themselves are undocumented in prose.

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%, and the description gives no parameter-level guidance. It implies target_configured_status through 'campaign status change', but campaign_id and ad_account_id are not explained, and the ACTIVE/PAUSED enum meaning is left entirely to the schema. With zero coverage the description should compensate and does not.

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 ('Prepare one campaign status change') and immediately distinguishes the scope from siblings by naming operations_confirm_campaign_status as the apply step and entities_prepare_update as the alternative for new work. An agent can tell this is the draft/approval stage of a two-phase campaign status mutation.

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?

Explicitly says when to use it ('Prepare one campaign status change... save an approval draft'), what must follow ('apply only after approval with operations_confirm_campaign_status'), and what to use instead for new work ('Prefer entities_prepare_update'). It also rules out a common misreading with 'This call does not change delivery.'

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