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

Annotations already declare readOnlyHint=true, destructiveHint=false and openWorldHint=true, so the safety profile is covered; the description nonetheless adds the returned payload shape (id, plan, status, subscriber), which is valuable because no output schema exists, and reinforces non-mutation with 'Changes nothing.' It stops short of covering pagination behaviour implied by 'limit'.

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 short sentences, front-loaded with the resource and return fields before the optional filter. 'Changes nothing' is slightly redundant with readOnlyHint but is brief and does not bloat the definition.

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 three-parameter, all-optional read tool with no output schema and full schema coverage, the definition supplies the resource scope, the filter behaviour and the returned fields. Pagination behaviour and the business-impersonation context are left implicit but are low risk.

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 schema already documents 'code' ('Only subscribers who typed this discount code'), 'limit' and 'business'. The description only restates the filter intent for 'code' and adds nothing about 'limit' pagination or the 'business' impersonation semantics. Baseline 3 is appropriate.

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 ('List subscriptions') and goes further by naming the returned fields (id, plan, status, subscriber). It is immediately distinguishable from mutating siblings such as agenta_subscriptions_cancel and agenta_subscriptions_change_plan.

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?

It gives one concrete usage condition - pass 'code' to narrow to subscribers who used a discount code - but offers no explicit when-not guidance and never names an alternative sibling (e.g. customers_list) that might serve a similar need. Usage is implied rather than fully routed.

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