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

Annotations already declare readOnly, idempotent, non-destructive, and closed-world, so the safety profile is covered. The description adds only the sort order (newest first) and the tenant scoping ("your"), and says nothing about pagination behavior or result shape beyond that. Useful but thin given annotations do most of the work.

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?

A single short sentence with the resource and ordering front-loaded. Nothing wasted, nothing that could be cut.

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 zero-required-param read-only list tool with full schema coverage, rich annotations, and no output schema, the description plus schema cover almost everything. The only real gap is routing guidance relative to invoice_recurring_read and invoice_recurring_create.

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% and both parameters (limit, cursor) are documented in detail there, including the legacy bare-array vs items/next_cursor distinction. The description adds no parameter information beyond that, which is acceptable at full coverage — baseline 3.

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+resource (list invoice_recurring rows) and adds a scope/ordering trait ("your", "newest first"). It is distinguishable from the sibling invoice_recurring_read (singular fetch) by the verb, though it never names any sibling explicitly.

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?

No guidance on when to use this versus invoice_recurring_read, invoice_list, or invoice_recurring_create. No prerequisites or exclusions are stated; the agent must infer everything from the tool name.

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