List Google Ads accounts

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 something beyond them: the result is scoped to what the 'signed-in user can access,' which discloses an auth-dependent, non-exhaustive result set an agent must account for. Return shape is only implied by 'customer IDs'.

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, zero filler, with the purpose front-loaded and the usage note following immediately. Every clause 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?

For a zero-parameter, side-effect-free list operation with rich annotations, the description supplies purpose, auth scoping, and the downstream use of the result. No output schema is needed because the return value ('customer IDs') is named explicitly.

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 tool takes zero parameters, so there is nothing for the schema to document and nothing the description needs to compensate for; the baseline is 4. The description correctly implies no filtering inputs are needed to get the full accessible list.

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?

States a specific verb and resource ('List the Google Ads customer IDs') plus an access qualifier ('the signed-in user can access'), so the scope is unambiguous. No sibling tool (check_connection, keyword/location/language tools) operates on this resource, so the agent can route here 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?

The second sentence gives an explicit use case: 'Use it to find the right GOOGLE_ADS_CUSTOMER_ID,' which tells the agent this is a discovery/prerequisite step. There are no stated exclusions or error-path guidance (e.g., what to do if the list is empty), which keeps it just below a 5.

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