Add subscriber to form by email address

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

Annotations already declare destructiveHint=true and idempotentHint=false, and the description adds genuinely useful impact context ('may affect delivery, audience membership, published data or irreversible state') plus the confirm gate. It stops short of stating exactly which of those side effects occur, keeping it out of 5 territory.

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 with the action front-loaded and no filler. The first sentence duplicates the title verbatim, which is minor redundancy but the second sentence earns its place by conveying risk and the confirm requirement.

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 7-parameter destructive mutation with no output schema, the description covers the safety-critical facts (impact domain, confirm requirement) while the schema carries the parameter detail, including the payload vs body-flag exclusivity. Only the choice between this and the by_id/bulk variants is left implicit.

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 71% and the schema already documents account, confirm, form_id, payload and payload_file. The description only echoes the confirm requirement (also in the schema) and implies email_address via the title phrasing, adding little beyond the structured fields.

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 (add subscriber to form) with the distinguishing qualifier 'by email address', which separates it from the sibling add_subscriber_to_form_by_id. The first sentence is an exact restatement of the title, so it breaks no new ground, but the resource and targeting method are unambiguous.

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?

Provides one real prerequisite ('Requires confirm=true') but offers no guidance on when to prefer this over add_subscriber_to_form_by_id or bulk_add_subscribers_to_forms. Usage is implied by the name rather than explained.

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