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

Annotations declare destructiveHint=true and readOnlyHint=false, so the agent knows this is a mutating operation, but the description adds nothing on top: no mention of what is overwritten, whether changes are reversible, or that a confirmation token is required. For a destructive write with annotations carrying only the safety flag, the description should disclose far more.

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?

Single short phrase, front-loaded and free of filler, but its brevity comes from omission rather than efficiency—it conveys no actionable detail beyond the name and title.

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 mutation tool with no output schema, an opaque nested 'patches' object, and a two-step confirmation flow, the description is far too thin to let an agent call it correctly without guessing. Critical information about valid patch contents and the confirm workflow is missing.

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 50% and the key parameter 'patches' is an undocumented nested object with no schema description, so the description must compensate and does not. It never explains what fields belong in 'patches' or how the preview/confirm_id handshake works.

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 gives a clear verb+resource ('Update a SP ad group') and the 'SP' qualifier does distinguish it from the SB/SD ad-group siblings. However, it says nothing about what aspects of the ad group can be updated, and the scope is so thin that it borders on restating the title.

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?

There is no guidance on when to use this tool versus ads_update_sp_campaign or the SB/SD update siblings, and no mention of the preview-then-confirm write flow that the schema implies. The agent must infer usage entirely from the name.

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