hostkit_add_invoice_line

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

With no annotations, the description must disclose behavioral traits, but it only states the action. It does not reveal side effects (e.g., that it modifies the invoice), required permissions, or constraints (e.g., invoice must be open). The agent gets no insight into what happens during execution.

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?

The description is extremely concise at 6 words, but it lacks structure beyond a single sentence. It is front-loaded with the core action, yet for a tool with 13 parameters, a bit more context (e.g., 'use this to add products or custom lines') would improve utility without harming conciseness.

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?

The description is incomplete given the tool's complexity. It does not clarify the relationship between parameters, what constitutes an 'open invoice,' or the overall effect on the invoice. Without output schema, the agent has no expectation of return value. More context is needed for correct usage.

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%, so each parameter is documented in the schema. The tool description adds no extra meaning beyond the schema. The baseline of 3 is appropriate since the schema handles parameter semantics adequately.

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 'Add a line to an open invoice' clearly states the verb (add) and resource (line to an open invoice). It distinguishes from sibling tools like hostkit_add_invoice (which creates a new invoice) and hostkit_close_invoice (which closes an invoice). The purpose is specific and unambiguous.

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 is provided on when to use this tool versus alternatives. It does not specify that the invoice must be open, nor does it mention any prerequisites or exclusions (e.g., not for closed invoices). The description does not help an AI choose this over other tools.

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