Send Campaign Test Email

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

Annotations already flag readOnlyHint=false and openWorldHint=true, so the safety profile is known; the description adds genuinely new behavior — the existing-subscriber validation constraint and the fact that override fields are ephemeral rather than persisted to the campaign. It does not mention whether test sends affect campaign analytics, logging, or bounce tracking, which are open questions for an open-world send.

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 sentences, front-loaded with the action and scope, then the override rule. Nothing is redundant or padded.

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 tool with a side effect, nine parameters and no output schema, the description covers the prerequisite and override semantics but leaves gaps around failure modes (unknown id, non-subscriber email), whether the send is recorded against the campaign, and what the call returns. It is adequate but not complete for its complexity.

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 only 33%, with body, subject, messenger, from_email, template_id and content_type undocumented. The description compensates at a high level by framing every optional parameter as a per-send override, which is the single most important semantic, but it never explains the meaning of messenger, template_id, or the content_type enum values.

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?

"Sends a one-off test copy of a campaign to specific subscriber e-mail addresses" gives a precise verb, resource and scope, and the word "test" distinguishes it from previewing or actually launching a campaign. It stops short of naming the sibling tools (e.g. listmonk_preview_campaign_draft, listmonk_update_campaign_status) that an agent might confuse it with.

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?

It states the key usage rule clearly: the campaign's saved fields are used unless you override them, and overrides apply only to this send. It also gives a prerequisite (recipients must be existing subscribers). It does not say when to prefer this over preview or over a real status change, so alternatives are left implicit.

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