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 mutation profile is known. The description adds the copy direction but omits notable behavior such as what happens on name collisions and the BROAD-to-PHRASE match-type conversion, which is only visible inside the dryRun schema field rather than in the description.

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 front-loaded sentence that states the action, the resource, and both directions with zero padding. Nothing could be removed without losing meaning.

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 five parameters, full schema coverage, and safety annotations, the description covers enough to invoke the tool correctly. It is slightly thin for a creating operation with no output schema — it says nothing about the result of the copy or the match-type conversion side effect, which an agent might otherwise assume is a verbatim duplicate.

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%, so defaults for name, sourceChannel, targetChannel, and dryRun are fully documented in the schema itself. The description's phrase 'from one search channel to the other' only mirrors the sourceChannel/targetChannel pair and adds no syntax or constraint detail beyond the schema, so baseline 3 applies.

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 names a specific verb (duplicate/copy), a specific resource (negative keyword list), and the exact scope (cross-channel, Google Ads ↔ Microsoft Ads). This scope is distinct from siblings like create_negative_keywords_list or add_keywords_to_negative_lists, so an agent can pick the right tool without opening the schema.

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 directional scope implies when the tool applies (copying an existing list to the opposite channel), but there is no explicit guidance on when to prefer it over create_negative_keywords_list plus add_keywords_to_negative_lists, and no stated prerequisites such as needing both channels connected.

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