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

Annotations mark this as a non-read-only write, and the description adds real context beyond them: what the address is used for (reports, payment and new-dialog notifications), the off-switch semantics, and the role requirement. It does not state what happens to a previously set address on overwrite, which is a minor gap.

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?

Three short sentences, front-loaded with the core action, then the audience constraint and the off-switch. No filler or redundancy.

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 two-parameter mutation with no output schema, the description covers purpose, precondition, and the disable behavior, which is enough to call it correctly. The only missing piece is confirmation of overwrite behavior on the target field.

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%: project_id is documented in the schema, but email only carries format constraints. The description compensates by explaining that an empty string disables notifications, which the schema's const "" does not convey, adding genuine meaning beyond validation rules.

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 (Set) and resource (the email where the platform writes to the OWNER), with a scope clarifier that it is never a client's address. An agent can distinguish this from sibling report/notification tools without opening the 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?

States the enabling case (empty string turns email notifications off) and a prerequisite (requires admin or owner role), giving clear context for when it applies. It does not name alternative tools, but the use case is unambiguous.

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