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

Annotations cover the safety profile (readOnlyHint, destructiveHint=false, openWorldHint), and the description adds genuinely useful traits beyond that: ordering ('newest first'), page size ('up to 50 invoices') and an auth prerequisite ('Cotlet API key with access to this app'). Return format is not covered, but pagination and auth are meaningful additions.

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-loads the purpose and keeps to short, scannable sentences with no filler. The inline restatement of the status enum is redundant against the schema's own enum, costing a little tightness.

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 read-only list tool with no output schema, the description still names the returned fields, ordering, page capacity, and auth requirement, covering everything needed to call it 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%, so baseline is 3, and the description adds value by showing how two filters interact ('past_due with due_before'). The verbatim status enum list largely duplicates the schema, which caps the score below 5.

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 ('Lists') and resource ('invoices') and enumerates the fields carried (client, status, total, balance, due date), so an agent knows exactly what it returns. It does not explicitly differentiate itself from the sibling jobber_get_invoice, which is the only gap.

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?

Gives a concrete usage pattern by combining filters: 'Use past_due with due_before to build a list to chase.' That is clear actionable context. It lacks any when-not-to-use or explicit alternative for a single-invoice lookup, so it stops short of full routing guidance.

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