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

Annotations already mark this as a non-destructive mutation with open-world behavior. The description adds meaningful context beyond that: it explains that the keyword blocks searches, details how EXACT/PHRASE/BROAD affect matching, warns that broad match types can block relevant searches, and clarifies that the negative is campaign-owned.

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?

The purpose is front-loaded, and the subsequent match-type explanation, warning, alternatives, and workspace note all earn their place. It is dense but not 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?

An output schema exists, so return values need not be described. The description covers the main behavioral risks, match-type semantics, workspace handling, and sibling alternatives; the main remaining gap is keyword format guidance.

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. It extensively explains the match_type values and notes that workspace is optional for single-workspace accounts, but it does not explain keyword formatting or add much detail about campaign_id.

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: adding a negative keyword to a campaign, with the effect of blocking search queries. It also distinguishes campaign-level negatives from shared and account-level negatives by naming the relevant alternative tools.

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 explicitly says when to use this tool (campaign-owned negative keywords) and when to use alternatives for multiple campaigns or account-wide negatives. It also warns that PHRASE and BROAD should only be chosen deliberately and disclosed to the user before creation.

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