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

Annotations already flag destructive/idempotent/openWorld, but the description adds substantive consequences: billing and shipping stop, prepaid cancellations are irreversible, Awtomic applies the cancel even if Shopify rejects it, and customer emails/SMS/webhooks may fire from the shop's automations. That is exactly the side-effect detail an agent needs before a destructive write.

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?

Front-loads the 'WRITE' signal and the core action, then layers usage gates, side effects, and the endpoint. Every sentence carries distinct information; nothing is padding.

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 mutation with no output schema, the description covers safety gating, irreversible cases, external side effects, divergence from Shopify state, and the sibling reactivation path. An agent can invoke it correctly and know the blast radius without further context.

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 100%, so reason, details, customer_id, and subscription_id are already fully documented with formats and examples. The description only restates the confirm_cancel=true requirement and adds nothing about the optional reason/details fields, so it does not exceed the schema baseline.

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?

Opens with a specific verb and resource ('WRITE: cancel one shopper's subscription contract in Awtomic') and immediately scopes it as the shop's customer subscription, not the API plan. It is clearly separable from siblings like awtomic_pause_subscription and awtomic_reactivate_subscription.

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?

Explicit gate: 'Only use it when the user explicitly asks to cancel this subscription, and confirm_cancel must be true.' It also names the reversal path (awtomic_reactivate_subscription) and its precondition (non-prepaid), which routes the agent between related tools.

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