Send batch

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

Annotations already declare readOnly=false, destructive=false, idempotent=false, openWorld=true. The description adds the most important non-annotation behavior: all-or-nothing atomicity, so one rejection cancels the whole batch, plus the 100-recipient ceiling. It does not cover rate limits, retry semantics, or what a caller can do about a partial rejection, keeping it below a 5.

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 sentences, zero waste, with the scope constraint front-loaded ahead of the atomicity caveat. Nothing repeats the title or the schema.

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 6-parameter mutation tool with no output schema, the description covers the critical atomicity and size limit but omits how the caller learns which recipients succeeded/failed, whether sends can be scheduled or cancelled via cancel_email, and any auth/verification preconditions. Adequate but with clear gaps.

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 only 50% and the description adds no meaning beyond the schema — 'per-recipient variables' is already documented on the batch/variables fields. The undocumented parameters (html, text, template_id) are left entirely to the schema, and the description never clarifies the subject-vs-template_id relationship.

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 (send) and resource (batch email) with concrete scope: 'up to 100 recipients, one email each, with per-recipient variables.' An agent can immediately distinguish this from send_email (single send) 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?

Usage is only implied — the 100-recipient / one-email-each framing suggests when batch sending applies, but the description never names send_email as the alternative for single sends or states prerequisites (e.g., verified domain on a live key). No explicit when/when-not guidance.

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