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

Annotations already declare readOnlyHint and destructiveHint=false, so the safety profile is covered. The description adds real behavioral context on top: default page size of 100, reverse ordering semantics (newest first), and the required cursor echo from next_cursor. It omits rate limits and whether the call fails on an expired cursor.

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 tight sentences with the resource and shape front-loaded, then paging behavior. No wasted clauses, though '(id, status, next billing date and more)' hedges rather than specifying, and the trailing 'GET /subscriptions' adds little for an agent.

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 burden for return shape and does so (fields plus page size), and pagination is fully explained for a list tool. Given three optional parameters and annotations covering safety, nothing an agent needs to invoke it correctly 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 coverage is 100%, so baseline is 3. The description still adds meaning the schema lacks: 'reverse' is clarified as reading the newest first (schema only says 'Read in reverse order'), and it explains the cursor chaining convention (pass next_cursor back as cursor) rather than just 'the next_cursor of the previous reply'.

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 the shop's subscription contracts') plus the returned fields and page size. It implicitly distinguishes itself from awtomic_get_subscription and awtomic_list_customer_subscriptions by scoping to the whole shop, though it never names those siblings explicitly.

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 sentence 'Use reverse to read the newest first' and the cursor round-trip instruction give operational guidance, but both are parameter-level instructions rather than when-to-use/when-not guidance. Nothing tells the agent to prefer awtomic_list_customer_subscriptions for a per-customer view or awtomic_get_subscription for a single contract.

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