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

Annotations already declare readOnlyHint=false with destructiveHint=false, and the description explains the resulting semantics that matter: staging only, no account change, a proposal_id plus preview returned, and a human-confirmation gate before apply_change. That is precisely the behavioral context an agent needs to avoid treating this as an immediate mutation.

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 sentences, both earning their place, with the non-mutation constraint front-loaded before the follow-up workflow instruction. 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?

Output schema exists and the description still names the two things an agent will act on (proposal_id and preview). Rich param coverage plus the description's confirmation-gate warning makes the definition complete for a 5-parameter proposal tool.

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 platform enums, entity_id, account_id and campaign_id semantics are fully documented in the schema, including the nested fields object and its currency note. The description adds no parameter-level detail, 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 verb and resource ("Stage a change to an existing ad set") and immediately clarifies the scope: it does not mutate the account but produces a proposal_id and preview. This separates it from the mutating sibling apply_change and from the generic propose_change without needing to open either 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 explicit sequencing and a gating condition: show the preview, then call apply_change(proposal_id) only after the user confirms. It does not explicitly say when to prefer this over the generic propose_change sibling, which keeps it short of a 5, but the workflow guidance is unambiguous.

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