Start Bulk Email

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

Annotations already declare destructiveHint=true and openWorldHint=true, so the safety profile is known. The description adds real value on top: it labels the operation as an irreversible real send, documents the readiness gate and human-authorization requirement, and explains that idempotency_key makes retries of the same approved action safe. It does not describe what happens on partial failure or how to stop a started wave, which keeps 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 with the most safety-critical word ('REAL SEND') first, followed by the gating conditions. No filler, no restatement of the title.

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 destructive, 13-parameter tool with no output schema, the description covers the authorization contract but not the lifecycle: it never says what is returned (job id / wave id) or which siblings to use afterward to monitor or cancel the send. Adequate to prevent accidental sends, but incomplete for operating the job it creates.

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 31% across 13 parameters, so the description would need to carry more weight. It correctly calls out three required parameters (recipient_target, idempotency_key, send_confirmation) and implies their contract, but says nothing about the other required parameters (campaign_id, subject, body_text) or the optional kind, threading, from_email, form_id, and attachments — all undocumented in both places.

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 uses a specific verb+resource ('start a campaign bulk-email job') and front-loads 'REAL SEND', which immediately distinguishes actual sending from the sibling gates check_bulk_email_readiness, get_bulk_email_job, and cancel_campaign_email_wave. An agent can tell what this tool does and what it is not without opening the 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 explicit preconditions: readiness must have passed and the user must have authorized sending, plus the required confirmation literal. It stops short of naming alternatives explicitly (e.g., 'run check_bulk_email_readiness first', 'use cancel_campaign_email_wave to stop'), so there is no stated exclusion list, but the usage context is unambiguous.

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