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

Annotations only declare the write/safety profile (readOnly=false, destructive=false, openWorld=true). The description adds genuinely useful behavior beyond that: the audience is dynamic and 'refreshed automatically as the journey data changes', and it is scoped by a lookback window — key facts for an agent deciding whether a live-syncing audience is appropriate. It omits credit cost, rate limits, and what happens if the segment is not yet READY.

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 with the action and resource first, then a colon introducing the mechanics. Every clause — dynamic, lookback window, auto-refresh — carries information the caller needs; nothing is padding.

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 non-destructive create tool with no output schema and fully documented parameters, the description covers what is produced, how it stays current, and how it is scoped. It stops short of saying what identifier is returned or whether segment readiness is validated at call time.

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 all four parameters are already documented, including the audience_type enum trade-off and the 1–365 lookback range. The description reinforces that lookback defines the evaluation window and the audience is company-derived, but adds no new syntax or format detail. 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?

States a specific verb and a precisely qualified resource: a dynamic Insights Retargeting audience built from a saved Insights (Spotlight) segment. That qualification separates it from the many other create_*audience siblings (firmographic, technographic, G2 intent, CSV upload), though no sibling is named explicitly.

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 'from a saved Insights (Spotlight) segment' — an agent can infer the prerequisite is an existing segment, and the schema reinforces this by requiring a READY segment id from list_segments / create_segment. However, the description names no alternatives (e.g. create_retargeting_audience, create_segment) and states no when-not conditions.

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