Draft a custom conversion goal

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

Goes well beyond the annotations: discloses that conversion actions are read-only during validation, that the goal is always created ENABLED, the exact dedup rule for name+actions, the `already_exists` result, and that REMOVED goals do not count. This is exactly the mutation-planning context the annotations cannot convey.

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-loads the key fact (PREVIEW) in the first sentence and orders the rest logically: bundling/read-only behavior, the ENABLED rationale, then dedup handling. Dense but every sentence earns its place; the trailing API documentation link is minor 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 draft/plan tool with an output schema (so return values need not be explained), the description covers creation scope, side effects, idempotency, and the confirm step. Nothing an agent needs to call it correctly 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 coverage is 100%, so the schema already documents name, customer_id, and conversion_action_ids. The description adds the meaningful name-dedup interaction (same name + same actions → already_exists; different actions → update tool), but little else about the individual parameters. Baseline 3 is appropriate.

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?

Opens with a specific verb+resource ("Create a custom conversion goal") and immediately discloses the crucial scope qualifier: it returns a PREVIEW. It distinguishes itself from draft_assign_custom_conversion_goal and draft_update_custom_conversion_goal by naming them and their roles.

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?

Explicit routing: use draft_assign_custom_conversion_goal to point campaigns at the goal, draft_update_custom_conversion_goal when a name exists with different actions, and confirm_and_apply to apply the returned plan_id. It also states the when-not case (REMOVED is meaningless, so there is "nothing to plan") and the idempotent already_exists path.

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