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

Annotations already establish read-only, non-destructive, closed-world behavior, so the safety profile is covered. The description adds genuinely non-obvious context: results reflect what is *implemented* per customer, and availability is explicitly not authorization or Google eligibility — a real trap for an agent that would otherwise treat a positive result as permission to create. It does not discuss result shape, though the output schema exists.

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?

Two sentences, no filler. The capability list is front-loaded and the caveat is a single tight clause. Every element 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?

An output schema exists, so return values need no prose explanation, and the description correctly focuses on scope and the availability/eligibility distinction. The only real omission is any hint about what connection_context does or when it must be supplied.

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 50%: customer_id is documented in-schema as a 10-digit id, and connection_context has only a regex pattern with no description anywhere. The phrase 'one owned customer' reinforces the required scoping parameter but adds little beyond the schema, and the second parameter is left entirely unexplained.

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?

Names a specific verb (Discover) and enumerates concrete resources: implemented campaign types, exact prepare/confirm tools, deployment gates, asset workflows. Scope is pinned to 'one owned customer,' which separates it from account-wide tools. It stops short of naming a sibling it supersedes, so it is clear but not fully differentiated.

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 framing implies this is a pre-flight discovery call before driving prepare/confirm workflows, and the closing caveat hints at when not to over-read its output. But there is no explicit 'call this before X' or 'use instead of Y' instruction, leaving the agent to infer the sequencing among 100+ siblings.

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