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

Annotations are minimal (readOnly=false, destructive=false), so the description carries real weight: it discloses the operator-only auth requirement, that existing accounts are NOT affected, and that null reverts to the install default. It does not spell out reversibility of a non-null assignment explicitly, but the null semantics largely cover it.

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?

The operator constraint and core behavior are front-loaded, followed by the exclusion and the sibling pointer. Two dense sentences with little waste, though the middle clause is information-packed.

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-param mutation with no output schema, the description covers scope, the null escape hatch, and the sibling boundary. The only minor gap is the absence of a stated return/reversibility note, but nothing essential for correct invocation 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% and already documents both params, so baseline is 3. The description nonetheless adds intent beyond the schema — that proxyId null means new accounts share the install default while existing ones stay put, and that email identifies the person whose future accounts are affected.

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+resource (sets the default proxy for new accounts a person adds) and explicitly distinguishes itself from the sibling li_set_account_proxy. An agent can tell exactly what changes and what does not without opening either 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?

Front-loads 'OPERATOR ONLY' as a usage constraint, then names the alternative (li_set_account_proxy) and the condition that selects it — moving a live account. When-to-use and when-not-to-use are both explicit.

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