Cancel subscription

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

Annotations already flag destructiveHint and openWorldHint, so the safety bar is partially covered, but the description adds genuinely new behavioral context: immediate vs end-of-cycle cancellation and a mandatory human-approval + confirm=true gate for live mode. It does not state whether an immediate cancel is irreversible or what happens on a failed/unknown subscription id.

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, zero waste, with the action and timing front-loaded and the safety gate second. Nothing to trim.

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 the critical decision points (timing, live-mode confirmation, human approval). Return-value behavior after success and failure modes are left unstated, which is the only real gap.

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 25%, so the description must carry the load. It does explain confirm (required true in live mode) and at_cycle_end (now vs cycle end), but adds nothing about provider beyond the enum's 'Gateway id' and nothing about provider_subscription_id format or where to obtain it.

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+resource ('Cancel a subscription') plus the scope choice ('now or at cycle end'), which cleanly separates it from the sibling payments_create_subscription. No sibling is named explicitly, so it lands at 4 rather than 5.

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?

Gives a concrete prerequisite: live mode requires confirm=true after human approval, and clarifies the two timing modes. It stops short of naming alternatives or when-not-to-use conditions (e.g. use payments_get_status first to verify the subscription exists).

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