Get Purchase Invoice

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

Annotations already declare readOnly, idempotent, openWorld=false and destructive=false, so safety is covered by structured data. The description adds nothing beyond that – no note on not-found behavior, ID provenance, or what record shape comes back.

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 front-loaded sentence with zero filler, but it is arguably too terse for the amount of behavioral information an agent needs, so not a full 5.

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 simple one-parameter read tool with full annotation coverage and no output schema, the definition is minimally sufficient. It still omits any detail about what the invoice ID refers to or what happens on a miss, which leaves a 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% with one parameter documented as 'Object ID'; the description's 'by ID' is a restatement. Baseline 3 is appropriate since the schema carries the full parameter burden.

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 a purchase invoice by ID'), which clearly separates it from list_purchase_invoices, create/update/delete_purchase_invoice. It does not explicitly name sibling tools or scope conditions, so it falls short of the 5 bar.

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?

There is no when-to-use guidance, no mention of the related confirm/invalidate/list tools, and no prerequisites. The agent must infer from the name that this is a single-record lookup rather than a list or mutation.

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