Send campaign

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

Annotations already declare destructiveHint=true, idempotentHint=false, and openWorldHint=true, but the description adds genuinely new behavior: the operation is irreversible once sending begins, the tool requests confirmation and reports the real recipient count, and a test is advised first. That is strong added context, though it omits details like rate limits or whether partially sent campaigns can be halted.

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?

Purpose is front-loaded and each labeled block carries distinct information (not-for, returns, use-when, caveat). The five-section formatting is slightly heavier than needed for a two-parameter tool, but no sentence is 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?

With no output schema, the description supplies the return behavior ('Confirmation that the send has started or been scheduled'), names the risky irreversibility, and covers the scheduling/immediate split. For a 2-parameter tool with annotations present, nothing an agent needs to call it safely is missing.

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 50%: only scheduledFor is documented in the schema ('ISO timestamp; omit to send immediately'), and the description adds no format or constraint detail beyond restating that scheduling is possible. Baseline 3 is appropriate since the schema already carries the one documented parameter's meaning.

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 states a specific verb and resource ('Send a campaign to its configured audience') plus scope (immediate or scheduled), and explicitly names the sibling it is not (plunk_test_campaign). An agent can distinguish it from plunk_test_campaign and plunk_send_transactional without opening any 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?

It gives both a negative route ('Not for: Checking how it will look — plunk_test_campaign...') and a positive precondition ('Use when: the draft is final, the audience is right...'), plus a 'send a test first' fallback. When-to-use, when-not-to-use, and the named alternative are all present.

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