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

Annotations declare destructiveHint=true and readOnlyHint=false, so the safety profile is partly covered, but the description adds non-obvious behavior the annotations cannot convey: omitted facts are inferred from the product and this costs credits, and the custom format triggers a written brief from the idea. It stops short of saying what an existing brief is replaced by.

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 tight sentences with the primary purpose front-loaded and the cost/deduction caveat placed before the custom-format branch. No filler, though the parenthetical fact list slightly lengthens the opening sentence.

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 7-parameter destructive mutation with no output schema, the description covers cost and the custom flow but omits what is overwritten by a re-set brief and says nothing about funnel_stage. It is workable but leaves a meaningful gap for a tool flagged destructive.

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 coverage is only 57%, and the description compensates by mapping the plain-language "who it's for, the benefit to sell, the action to drive" onto target_audience, benefit_to_highlight and primary_ad_goal, plus explaining idea's role. funnel_stage remains undefined in both places.

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 ("Sets the ad's format and campaign facts") and immediately enumerates the facts in parentheses, so the agent knows exactly what the call accomplishes. It does not name an alternative sibling to disambiguate against, though it does point to list_formats as the source of format values.

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 conditional guidance for one path ("For the `custom` format pass `idea`") and notes format is required the first time, which implies repeated invocations. However there is no explicit when-to-use/when-not relative to siblings like create_project or generate_script, so the routing is mostly implied.

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