send_email

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

With no annotations, the description bears the full burden of behavioral disclosure. It mentions the cost of 1 credit per send and that it uses the connected email account, but it does not disclose the confirmation flag required to actually send, potential irreversibility, or error behaviors. It adds some value but lacks depth for a mutation with side effects.

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 description is two sentences, front-loaded with purpose, and includes critical cost and alternative information in a compact form. Every word earns its place with no fluff.

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 send operation with 100% schema coverage, the description provides essential context (cost, one-off scope, alternate tool for bulk). It does not describe the return value, but no output schema exists, and the core behavior is adequately covered. Missing a direct mention of the confirmation requirement, but that is fully documented in the schema, so not a critical 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 description coverage is 100%, so the baseline is 3. The description does not add any parameter-specific meaning beyond what the schema already provides, and it does not compensate for any gaps since there are none. Thus a 3 is appropriate.

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?

The description clearly states 'Send a one-off email through your connected email account', specifying the verb and resource. It also distinguishes itself from bulk sending by explicitly naming campaigns as the alternative, making sibling differentiation strong.

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 description provides explicit usage guidance by stating 'For bulk sending, use campaigns instead', naming the alternative tool and defining the boundary between one-off and bulk scenarios. Context is clear and exclusions are stated.

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