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

Annotations already declare destructiveHint=true and openWorldHint=true, so the safety profile is known. The description adds which positions and surfaces can be set, but says nothing about what existing placement settings are overwritten, whether ad review is re-triggered, or what permissions/account context are required — meaningful gaps for a destructive 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?

A single front-loaded sentence that packs the mode switch, the surfaces, and example positions with no filler. It is dense but readable, and nothing is wasted.

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, 9-parameter mutation with no output schema and low schema coverage, one sentence is not sufficient: it omits the automatic-vs-manual precedence rule, account/folder scoping, device targeting, and the consequence of overwriting existing placements.

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?

The description implicitly maps the platforms, facebook_positions and instagram_positions parameters by enumerating the surfaces (Facebook, Instagram, Messenger, Audience Network; feed, stories, reels). With only 33% schema coverage, it does not compensate for the undocumented remainder — notably the precedence of `automatic` over the position arrays, plus devices, folder, account and language.

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?

Names a specific verb (switch) and a specific resource (ad set placements), and spells out the two modes (Advantage+ automatic vs manual) plus the surface types covered. It is clearly distinguishable from sibling targeting tools like meta_update_targeting, though it never names that sibling explicitly.

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?

The description implies the two use modes (automatic vs manual) but gives no explicit when-to-use, prerequisites, or alternatives. An agent must infer that manual position arrays only matter when automatic is false, and that other ad-set attributes are handled by different tools.

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