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

Annotations already declare readOnly, idempotent, and non-destructive, so the safety profile is covered. The description adds a real behavioral caveat the annotations cannot convey: amounts are bare numbers with no currency attached, and where to resolve the currency. That is meaningful context beyond structured fields.

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 sentences, zero filler: the first front-loads what the tool returns, the second front-loads the one gotcha an agent would otherwise get wrong. Every clause earns its place.

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 correctly assumes the burden of summarizing the return payload and does so adequately for a single-entity get. The main omission is any mention of error behavior for a missing/invalid invoice id, which is minor for a read tool.

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?

Single required 'id' parameter with 100% schema description coverage ('Invoice ID', uuid format), so the schema carries the load and the baseline is 4. The description adds nothing about the id itself but needs to add nothing.

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 ('Get detailed invoice information') and enumerates what comes back (amounts, dates, vendor, project, purchase order). It does not explicitly contrast itself with the sibling list_invoices, but the word 'detailed' and the singular id parameter make the distinction inferable.

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 one actionable routing rule — call get_organization_settings for currency_code before stating an amount — which is genuinely useful. However, it never says when to use this tool versus list_invoices or when not to use it, so usage context is only partial.

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