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

Annotations already cover the safety profile (readOnly, non-destructive), and the description adds real value beyond them: the constraint that only supported accounts can be booked, that unsupported accounts cause rejection, and an explicit auth requirement (Cotlet API key with access to this app). It omits return format and pagination, keeping it from a 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?

Front-loaded with the resource definition and the key precondition, but the opening two clauses ('The chart of accounts: account numbers and names you can book on. Returns the accounts...') restate the same idea, adding a little redundancy.

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 filterable read-only list tool with annotations covering the safety profile and a fully documented single parameter, the description is essentially complete. Pagination/volume behavior is not mentioned, but with no output schema this is a minor gap.

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% for the single 'search' parameter, so the schema already carries the semantics. The description's mention of 'account numbers and names you can book on' only loosely implies what is searchable; it adds no syntax or matching rules beyond the schema. 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?

States a specific verb (returns/lists) and resource (accounts of the company's chart of accounts) with the returned fields (number and name). An agent can distinguish this from sibling bokio_list_customers, bokio_list_invoices, and bokio_list_journal_entries without opening a schema.

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?

'Check here first' plus the reason (Bokio rejects journal entries on unsupported accounts) gives clear context for when this tool is needed – before creating a bokio_create_journal_entry. It stops short of naming alternatives or stating when-not to use it, so it is not a full 5.

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