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

Annotations already declare readOnlyHint=true, destructiveHint=false, openWorldHint=false, so the safety profile is covered. The description adds genuine value by disclosing the key output side effect (yielding conversion_customer_id needed for writes) and the 'effective' customer scoping, but says nothing about pagination, limit behavior, or result shape.

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 short sentences with no padding, and the core action plus its scoping qualifier are front-loaded. The second sentence is slightly terse ('required for writes' leaves the specific write workflow implicit) but 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?

Without an output schema, the description usefully names one returned value, but omits the rest of the return shape, pagination/limit semantics, and how connection_context should be supplied. Adequate for a simple list tool but with clear gaps.

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 only 33% – only customer_id is documented. The description adds no meaning for the two undocumented parameters (limit with its default/max, and connection_context with its mctx_v1 pattern), so it fails to compensate for the coverage gap on a 3-parameter tool.

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?

Specific verb+resource ('List conversion actions') plus a scoping qualifier ('for the effective Google Ads conversion customer'), which tells an agent this lists existing conversion actions rather than creating/updating one of the many sibling conversion_action_* tools. It stops short of explicitly naming the confirm/prepare siblings it complements, so it is clear but not maximally 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 clause 'Returns the conversion_customer_id required for writes' implies this is a prerequisite call before conversion-action write flows, which is useful implied usage. However, it never states when to choose this over alternatives (e.g., accounts_list), nor any preconditions or exclusions.

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