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

Annotations already declare readOnlyHint=true and openWorldHint=true, so safety is covered. The description adds value by disclosing that the response includes lines, taxes and payments, but says nothing about auth, missing-id behavior, or error cases.

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?

Two short sentences, front-loaded with what is returned, then the endpoint. No waste and nothing buried.

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 usefully previews the response composition (lines, taxes, payments), which is the main thing an agent needs beyond the trivial single-parameter schema. Minor gap on error/not-found behavior.

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% with a single documented 'id' parameter, so the schema carries the semantics. The description's '{id}' path template merely restates it without adding format or sourcing guidance (e.g., where to obtain the id).

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 a specific verb and resource ('One sales invoice') and adds the returned content shape (lines, taxes, payments), making it distinguishable from the list_* siblings. It stops short of explicitly naming the alternative tool, but the singular scoping is clear.

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?

Usage is only implied: 'one sales invoice' plus the path template conveys fetch-by-id rather than list. There is no explicit when-to-use or when-not-to-use guidance versus jurnal_list_sales_invoices.

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