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

Annotations already flag destructiveHint=true, readOnlyHint=false and openWorldHint=true, so the safety bar is low, yet the description still adds real behavioral context: creatives cannot be edited in place, a new creative is cloned and attached, and the ad re-enters review while retaining its status. It stops short of saying what happens to the superseded creative or whether existing performance history is preserved, which is the main remaining gap given the destructive flag.

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 tight sentences: the first front-loads what can be changed, the second explains the non-obvious mechanism. No filler, no repetition of the title, and the important constraint arrives before the detail.

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 destructive, open-world mutation with no output schema and nine parameters, the description covers the essential non-obvious facts: the clone-and-attach mechanism, the review reset, and status retention. It is only slightly incomplete in not clarifying the ad identifier format or the account/folder scoping, which the schema handles thinly.

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?

With only 33% schema description coverage, the description must compensate, and it does partially by naming the five editable creative fields (primary_text, headline, description, link, call_to_action) that map to schema properties. It says nothing about the required 'ad' identifier, nor about folder/account/language, so several parameters remain unilluminated 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?

The description opens with a specific verb and resource ('Change an ad's primary text, headline, description, link or call to action') and enumerates exactly which creative fields are editable. That field list cleanly separates it from sibling mutations such as meta_rename, meta_set_status, meta_update_targeting, and meta_create_ad.

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?

Usage is implied rather than stated: the agent can infer this is the tool for copy/link edits because the mechanism ('builds a new creative from the current one') is spelled out. There is no explicit when-not guidance pointing to meta_update_targeting, meta_update_placements, or meta_create_carousel_ad for other kinds of ad changes.

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