send_email_batch

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

With no annotations, the description carries full behavioral burden. It does add real value: 'one id per accepted email' implies non-atomic partial success, and the 100-item ceiling is stated. But it says nothing about rate limits, permission/domain verification requirements, or what happens to entries that are not accepted.

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?

Two tight clauses with no filler; the batch cap and the send_email shape reference are front-loaded. Every sentence earns its place.

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?

There is no output schema and no annotations, so the description is the only source for return behavior, and it gives just one clause ('one id per accepted email'). For a batch send operation, missing details about partial failures, error reporting per entry, and delivery semantics leave the agent under-informed despite the rich input schema.

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% and the two top-level parameters are thoroughly documented there, including the idempotency-key semantics (409 on reuse with a different payload). The description adds only the cross-reference to send_email's entry shape, so the baseline 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?

States a specific verb and resource (send emails) plus batch scope (up to 100 in one call) and ties the entry shape to the send_email sibling. It distinguishes the batch case implicitly, but never explicitly says to prefer this over send_email for multiple sends, so sibling routing is left to inference.

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 'up to 100 emails in one call' phrasing implies when this tool is appropriate (bulk sending), but there is no explicit when-to-use/when-not guidance, no threshold telling an agent to use send_email for a single message, and no prerequisites or limits on concurrent batches.

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