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

Annotations only declare readOnlyHint=false and destructiveHint=false; the description goes well beyond them by stating the operation copies rather than references, that editing the returned profile never mutates the library master, that a same-named profile yields the existing copy (idempotent behavior), and that write scope is required.

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?

Four short sentences, front-loaded with the action, then the return semantics, then the idempotency edge case, then the auth requirement. Each sentence contributes distinct information with no filler.

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 two-parameter mutation tool with no output schema, the description covers what is produced (the campaign's own target profile copy), what is not affected (the library master), the duplicate-name case, and the scope requirement. Nothing an agent needs before invoking it is missing.

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%, with both parameters documented as UUIDs including the campaign-state constraint, so the schema carries the parameter burden. The description adds no per-parameter detail such as format or naming rules, which is the expected baseline of 3 here.

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 opening sentence gives a specific verb and two concrete resources: copying a library audience into a campaign, which inherently separates it from create_audience and add_campaign_contacts. It does not name any sibling or explicitly contrast with one, so it falls just short of the top band.

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 the copy semantics plus the prerequisite 'requires write scope' and the constraint that the campaign must not be completed or deleted (in schema). There is no explicit when-to-use versus when-not, and no named alternative for cases such as creating a new library audience instead.

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