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

Annotations already declare the mutation/non-idempotent/open-world profile, and the description adds real context on top: the payment-gated activation flow and the Stripe checkout return (cards + PayNow). It does not cover what happens on repeat calls or renewal after the 12 months, so it falls short of full disclosure.

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, front-loaded with the action, scope, and cost, then the return/activation behavior. The price enumeration is dense but each entry is decision-relevant, so little is wasted.

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?

With no output schema, the description carries the return burden and does so ('Returns a Stripe checkout URL... activates on payment'), plus all three required inputs are named. Missing only post-payment behavior details such as renewal or failure handling.

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 the baseline is 3. The price-per-plan list adds useful meaning for the 'plan' parameter, but its labels ('business-name', 'IPOS-filing') do not match the schema's enum values ('trademark', 'ipos-watch'), which introduces mild ambiguity rather than clean added semantics.

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 ('Start a prepaid 12-month Watchtower watch') with scope, pricing tiers, and what is produced. It is unmistakably distinct from siblings like create_audit, pay_audit, or lookup_ownership without needing their schemas.

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?

The description states prerequisites ('Needs the target + delivery email') and the activation condition ('activates on payment'), which implies when it applies. However, it never contrasts itself with plausible alternatives (e.g., pay_audit for payment, create_audit for one-off checks) or states when not to use it.

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