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

Annotations already declare readOnlyHint, idempotentHint and destructiveHint=false, so the safety profile is covered. The description adds genuine domain behavior beyond that: it explains what 'primary' means (what Smart Bidding optimises toward) and warns about the zero-conversion outcome when no enabled primary action exists, which is non-obvious cause-and-effect context.

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 tight sentences: the first front-loads what is returned, the second delivers the high-value edge case. No filler, no repetition of the title, and the most actionable warning is placed last for emphasis.

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?

With no output schema, the description correctly compensates by enumerating the returned fields, and annotations cover safety. The only real gap is the undocumented customer_id parameter, so the agent lacks guidance on how the target account is identified.

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 0% and the single required parameter, customer_id, is never mentioned or explained in the description. With only one parameter, the description could easily have clarified which account identifier it expects, but adds nothing beyond the schema.

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 description states a specific resource (every conversion action in the account) and enumerates exactly what it reports back: type, category, status, primary flag, counting and default value. An agent can distinguish this read-oriented listing from siblings like ads_create_conversion_action and ads_update_conversion_action without opening any schema.

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?

There is no when-to-use guidance or routing to alternatives. It never says to prefer this over ads_report for conversion data, nor that create/update siblings exist for modifying these actions. Usage must be inferred entirely from the name.

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