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

Annotations already declare readOnlyHint=true, openWorldHint=true, and destructiveHint=false, so the safety profile is covered. The description adds useful behavioral context beyond that: it states the return shape ({ count, next_skip, items }) and explains the pagination convention of passing next_skip as skip, which is valuable because there is no output schema.

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?

The description is compact and front-loads the resource and return shape before covering paging, single-record reads, filtering, and the endpoint. Every sentence contributes, though the terse field list at the start is slightly cryptic.

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 six-parameter read-only list tool with no output schema, the description covers the important gaps: return shape, pagination continuation, single-record access, filtering modes, and the underlying GET endpoint. It is not fully complete on sibling differentiation or auth/rate-limit context, but it gives an agent enough to call the tool correctly.

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%, and the schema already documents id, skip, sort, limit, query, and filters in detail. The description reinforces the main workflows (read one record, page with next_skip, exact-match filters or MongoDB-style query), but it largely restates schema-level information rather than adding new parameter semantics, so the 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?

The description clearly identifies the resource as recurring invoice subscriptions and names key fields (client, schedule, amount). It does not explicitly distinguish this from the sibling plutio_list_invoices, but the recurring-subscription framing is specific enough to separate it from generic invoice listing.

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 gives operational guidance for reading one record, filtering, and paging, but it does not explicitly say when to use this tool versus plutio_list_invoices or other list tools. Usage is implied by the resource name rather than stated with alternatives or exclusions.

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