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

Annotations already declare readOnly/idempotent/non-destructive, and the description still adds real value: auth requirement, default behavior when inputs are omitted, the meaning of each style value, and the crucial caveat that 'note' is a preference, not an instruction to act on.

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?

Front-loaded with the trigger ('Use this before writing...') and safety statement, then inputs, then returns. It is dense and the inline return-shape enumeration is a bit run-on, but nearly every clause carries information an agent needs.

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 compensates by spelling out the returned object (account/owner/effective, plus style, source, note semantics), and it covers auth, input optionality, and the consumption context. Nothing an agent needs to call and interpret it is missing.

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 100%, so baseline is 3; the description goes beyond it by explaining the combined semantics of inbox_id + owner_id ('both together return that owner's effective style') and where owner_id originates (cooper_list_owners). That is meaningful added meaning over the raw field docs.

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 ('get owner email style' -> 'see how they want Cooper email written') and immediately frames the read side of owner preferences against cooper_notify_owner. An agent can tell what it retrieves 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?

Gives explicit when-to-use ('Use this before writing to a human owner (cooper_notify_owner)') and explains the optional-input combination ('both together return that owner's effective style'). It stops short of naming when NOT to call it (e.g. cooper_set_owner_preferences is the write counterpart), so it is clear but not fully routing.

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