mailer_config_update

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

Annotations already declare idempotentHint=true, destructiveHint=false, readOnlyHint=false, so the safety profile is covered; the description adds real value beyond that with upsert semantics, the password-retention rule on update, and the downstream consequence that client-facing documents are sent through this SMTP server. It stops short of saying whether credentials are validated before saving or what happens on a failed connection.

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 action and resource, then the consequence, then the one non-obvious operational rule. No filler.

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 8-param, zero-required upsert tool with no output schema, the description covers plan gating, create-vs-update behavior, and the password edge case. It leaves out validation/error behavior and whether saving is transactional with mailer_config_test, which is a modest remaining gap.

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 every parameter including host, port, encryption enum, and fromAddress is already documented. The description's one added hint — omitting the password keeps the saved one — duplicates the schema's own 'omit to keep the saved one' text, so it adds no meaning beyond the structured fields.

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 pair ('Create or update') and resource ('the organization's custom email sender'), and its effect on outbound invoice/receipt/delivery-note mail is spelled out. An agent can immediately distinguish it from the read-only mailer_config_get, mailer_config_test, and mailer_config_delete siblings.

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 plan gating ('Business plan only') is a useful prerequisite, and the upsert framing implies when to reach for it. However, it never names alternatives or exclusions — e.g. that mailer_config_test should be used to verify credentials, or that mailer_config_get reads the current config — leaving routing to inference.

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