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

Annotations already declare readOnlyHint=true, destructiveHint=false and openWorldHint=false, so the safety profile is covered and the description carries a lower bar. It nonetheless adds nothing beyond the name: no indication of whether families are static or connection-scoped, and no return shape (there is no output schema either).

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 no filler, which is proportionate for a simple read-only listing tool. The sparseness is a completeness problem more than a structural one, so it stays at 4 rather than 5.

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 one-parameter, no-output-schema listing tool, an agent still needs to know what a "family" is and what the response looks like, neither of which is stated. Safety behavior is covered by annotations, so the remaining gap is the opaque connection_context and undefined return values.

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?

The single parameter connection_context has 0% schema description coverage and a strict regex pattern, yet the description says nothing about it — not whether it is optional, what a connection context represents, or when it must be supplied. With a parameter present the baseline-4 zero-parameter allowance does not apply, and the description fails to compensate.

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 gives a specific verb and resource ("List supported deep-analysis families"), which is clearly distinct from the sibling google_ads_deep_analysis_query/export that consume those families. It stops short of naming that relationship explicitly, so an agent must infer that this is the enumeration step preceding a deep-analysis query.

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?

No when-to-use guidance, no prerequisites, and no mention of the two obvious sibling tools (google_ads_deep_analysis_query, google_ads_deep_analysis_export) that the returned families presumably feed into. The agent is left to guess why it would call this list.

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