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

Goes well beyond the annotations: it discloses that all of the customer's future bookings made with the subscription are cancelled, that the renewal date shifts forward by the frozen days unless Preserve Payment Schedule is on, and that a privileged staff account plus confirmation is required. These side effects and auth constraints are exactly the behavioral context annotations (readOnly=false, openWorld=true, destructive=false) do not convey.

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, but the first two sentences are near-duplicates ('...now or on a date, with an optional unfreeze date' vs '...now or from a date, and unfreezes it on unfreeze_on if set'), and policy boilerplate about confirmation/API keys takes up a large share of the text. Some trimming would sharpen it.

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 mutation tool with no output schema, it covers side effects, renewal behavior, permissions, and confirmation requirements well. It leaves minor gaps such as behavior when a membership is already frozen or the exact response/error handling, but nothing essential to correct invocation 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 description coverage is 100%, so the parameter meanings are already documented. The description echoes the timing semantics ('now or from a date', 'unfreezes on unfreeze_on') without adding syntax or edge-case detail beyond the schema, so the baseline 3 applies.

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 ('Freeze a customer's subscription') plus timing scope (now or on a date, optional unfreeze date), which lets an agent distinguish it from Momence siblings like cancel_membership_renewal or cancel_booking 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?

Gives clear situational context and prerequisites ('Needs a staff account allowed to freeze', confirm-each-call default, Cotlet API key with app access), but never names an alternative or an explicit when-not condition (e.g., when to cancel vs freeze), so an agent gets context without routing guidance.

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