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

Annotations already cover read-only safety, but the description adds genuinely useful behavior: the return envelope { count, next_skip, items } and the pagination contract of feeding next_skip back as skip. That is context an agent cannot get from the annotations.

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?

Telegraphic fragments, but every clause carries information: fields, return shape, pagination step, single-record mode, filter modes, endpoint. Dense and front-loaded with no filler, though the fragment style costs a little readability.

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 steps in to explain the response envelope and paging, which is exactly what's needed for a paginated list tool. It leaves sort/limit details to the schema, which already documents them fully.

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, but the description goes slightly beyond by naming concrete filterable fields (amount, currency, client, invoiceId, status, type, issueDate), which helps an agent choose filter keys rather than guessing.

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 states the resource (transactions / GET /transactions) and scopes it to payments and expenses, then enumerates the fields available. It's clear what the tool returns, though it never explicitly says 'list' in prose and doesn't differentiate itself from the many other list_* siblings beyond naming the domain.

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 implied usage: pass id to read a single record, use exact-match filters or a MongoDB-style query to filter. However it never states when to use this versus plutio_list_invoices or plutio_list_invoice_subscriptions, which is the main ambiguity in this sibling set.

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