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

Annotations declare readOnlyHint=false and destructiveHint=false, so the safety profile is partly covered. The description adds the important non-obvious behavior that this is a staged two-phase write (preview vs apply), which the annotations do not encode. It does not mention idempotency (annotations say false, so re-adding duplicates may occur) or per-call keyword limits.

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 fragments with zero filler; the core action comes first, followed by the match_type values and the confirm semantics. Every sentence carries information an agent needs.

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?

An output schema exists, so return values need not be explained. But for a 6-parameter mutation tool with 0% schema coverage and no annotations covering the staged-write behavior, gaps remain around keyword format, account/customer identifier roles, and duplicate handling.

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 description coverage is 0%, so the description must compensate and it only partly does: it enumerates match_type values (Broad | Phrase | Exact) and explains confirm, but says nothing about account_id, ad_group_id, customer_id, or the keyword string format. Half the parameters remain undocumented anywhere.

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: 'Adds keywords to an ad group.' The tool name/title carries the Microsoft platform, so an agent knows it targets Microsoft Ads. However, it does not distinguish itself from the sibling add_keywords (generic) or manage_keywords, leaving the platform routing partly implicit.

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 'confirm=false = preview, confirm=true applies' line gives a real usage rule for the dry-run flow, which is the closest thing to when-to-use guidance. But it never states when to prefer this tool over add_keywords or manage_keywords, and there is no prerequisite or exclusion guidance.

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