fiken_get_invoice

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

The description confirms read-only behavior consistent with the readOnlyHint annotation but adds no further behavioral context (e.g., authentication requirements, rate limits, or response structure).

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, clear sentence front-loads the essential information with no extraneous words.

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 retrieval tool with one parameter and a readOnly annotation, the description is minimally adequate but omits typical return value details (e.g., invoice fields, pagination) which are not covered by an output schema.

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?

Despite 0% schema description coverage, the description only mentions 'by ID' without explaining the invoiceId parameter's format or purpose, leaving the agent to infer from the name alone.

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 'Returns a specific invoice by ID' clearly identifies the action (returns), resource (invoice), and identifier (ID), distinguishing it from sibling tools like fiken_list_invoices or fiken_create_invoice.

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?

The description implies usage for retrieving a single invoice but provides no explicit guidance on when to use this tool versus alternatives (e.g., when to use fiken_get_invoice vs fiken_list_invoices).

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