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

Annotations already declare readOnlyHint/openWorldHint/destructiveHint=false, so safety is covered. The description adds value beyond them by disclosing the return shape { count, next_skip, items } and the pagination contract (pass next_skip as skip), which the annotations cannot convey. Missing details like auth or rate limits keep it below 5.

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 dense and front-loaded: fields first, then return shape and paging, then id/query usage, then the endpoint. The leading field enumeration is somewhat list-like, but every sentence carries information.

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 present, the description usefully explains the response envelope and paging. All 7 parameters are covered by the schema (including the nested filters object), so the description is adequate for correct invocation. Deeper behavioral details (e.g., max page-size interplay with limit) are left implicit.

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 id, skip, sort, limit, query, status and filters. The description's notes on status values and MongoDB-style queries restate rather than extend 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?

The description names the resource and enumerates the fields an invoice carries (name, client, status, amount, dueDate, etc.), plus the endpoint GET /invoices, so the agent knows it is a read/list of invoice records. It does not explicitly distinguish itself from siblings such as plutio_list_invoice_subscriptions or plutio_create_invoice, which is what a 5 would require.

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?

'Pass id to read one record. Filter with exact-match fields or a MongoDB-style query' gives clear guidance on how to select records with the flexible parameters. There are no explicit when-not-to-use notes or named alternatives for other invoice operations.

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