Add keywords to an ad group

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

Annotations already declare readOnlyHint=false, destructiveHint=false and openWorldHint=true, and the description adds real context beyond them: it warns that the call mutates a live account and documents a confirmation gate for bulk inserts. It still does not say whether existing keywords are merged or replaced, which matters given idempotentHint=false.

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?

Front-loaded with purpose and the live-account warning, then scoped detail on keyword format and match types. The unusual blank-line/stanza layout adds a little noise but nothing is redundant.

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?

With an output schema present, return values need no explanation, and the description covers the mutation, the input shape, the enum values and the bulk confirmation requirement. The remaining gap is the role of ad_account_id and merge-vs-replace semantics in a non-idempotent 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?

Schema coverage is 0%, so the description must carry the load, and it does cover the hardest parameter well: keyword input may be plain strings (using match_type) or objects like {"value": ..., "match_type": ...}, with BROAD/PHRASE/EXACT enumerated and confirm='APPLY' explained. ad_group_id, ad_account_id and the default value of the confirm field are left entirely to the bare schema.

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 states a specific verb and resource ('Add targeting keywords to an ad group') and makes the effect explicit ('Changes the live account'). It does not name the sibling alternatives (create_negative_keywords, suggest_keywords, list_keywords), so an agent must infer the boundary, but the operation itself is unambiguous.

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 by 'Add targeting keywords to an ad group', and the bulk threshold rule ('More than PINTEREST_ADS_BULK_THRESHOLD keywords need confirm=APPLY') gives a concrete precondition. There is no explicit when-not guidance or pointer to sibling tools for listing, suggesting, or adding negative keywords.

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