Edit ad

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

Annotations only declare write/non-destructive/open-world; the description adds real behavioral context the agent could not get elsewhere: the update is a merge (unmentioned creative fields preserved) and a creative edit triggers re-review. It also explicitly excludes status mutation, which is the most likely mistaken assumption for a tool named update_ad.

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 short sentences, front-loaded with the editable scope, then the merge rule, then the side effect and the exclusion. Every sentence carries distinct information with 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 9-parameter mutation with no output schema, the description covers the important semantics: partial-update behavior, the re-review consequence, and the status exclusion. The remaining gaps (price, return value, permission requirements) are modest given the annotations already flag it as a non-destructive write.

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 11% schema description coverage, the description must carry the parameter burden, and it does map most fields to concepts: name, title/body (creative), link, image, and tracking template (query_string_template). But it never mentions price, does not disambiguate file_id versus image_url, and gives no format hints, leaving a real gap for a 9-parameter tool.

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?

"Change an ad name, its creative (title, body, link, image) or tracking template" gives a specific verb, resource, and an enumerated field scope. The closing "Never changes status" draws a hard boundary against the sibling status tools (pause_ad, archive_ad) without needing the 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?

It clearly frames the tool as a partial edit ("Creative fields you do not mention are kept") and rules out status changes, which tells the agent when to reach for a status tool instead. It stops short of naming the alternative or stating prerequisites, so the routing is implied rather than explicit.

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