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

Annotations already declare readOnlyHint=false, destructiveHint=false and openWorldHint=false, so the safety profile is covered. The description adds only 'in the Metadata platform with Google Ads integration', which is thin for a mutation and arguably narrows scope in a way the channel parameter contradicts; it says nothing about validation limits on keywords, whether creation is idempotent, or what is returned.

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 compact sentence with no filler, front-loading the verb and resource. It is not padded, though its brevity leaves no room for the routing or lifecycle 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?

For a mutation tool with no output schema, the description should say what comes back (e.g. the new list's identifier) and what state the result is in. Neither the return value nor the standalone-vs-attached lifecycle is addressed, leaving the agent to guess the next step after creation.

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 100% and the channel enum itself explains the per-channel isolation and default, so the heavy lifting is done structurally. The description adds no parameter meaning and its 'Google Ads integration' phrasing points away from the supported MICROSOFT_ADS option, so baseline 3 rather than higher.

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 plus resource ('Create a new negative keywords list') and names the platform, so the basic action is unambiguous. It does not distinguish itself from close siblings such as duplicate_negative_keywords_list or add_negative_keyword_lists_to_live_campaigns, which an agent must infer.

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?

No guidance on when to use this versus duplicating, listing, or attaching an existing list to campaigns. The critical workflow fact — that a newly created list is standalone and must be pushed live via add_negative_keyword_lists_to_live_campaigns — is absent.

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