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

Annotations already declare this is a non-destructive, non-read-only mutation. The description adds useful behavioral details beyond annotations: it returns the saved public item (null after removal) and the complete working scanConfig, and it discloses that creating a definition does not assign it to prompts and does not launch a Scan.

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 the core purpose and packed with useful guidance in a few sentences. Minor grammar issue ('a audience') and the 'Returns...' sentence is somewhat dense but still earns its place.

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?

The output schema exists, so return values need not be explained, yet the description does so anyway. It omits guidance on aliases and description parameters and does not state constraints (e.g., name uniqueness, max aliases), leaving it incomplete for a four-parameter creation tool.

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 only 25%, with only siteId documented in the schema. The description does not explain the name, aliases, or description parameters at all, leaving significant gaps that the description should compensate for given the low coverage.

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 ('Create') and resource ('audience segment') with scope ('on a Site or Topic'), and explicitly distinguishes itself from create_prompt by noting that the definition is not assigned to prompts. An agent can identify what this tool does without reading siblings.

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?

Provides clear context: read get_scan_config.personas for definitions and IDs, and pass the returned item.id to create_prompt to assign it. Also clarifies that no Scan is launched. Lacks explicit exclusion guidance versus update_persona or remove_persona, but the intended usage is evident.

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