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

Annotations already declare readOnlyHint=false and openWorldHint=true, so the write/external nature is known. The description adds real value beyond that: it explains the invoice reaches the buyer who is asked to pay, requires per-call confirmation by default, and needs a scoped Cotlet API key. This is useful side-effect and auth context.

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 purpose is front-loaded, which is good, but the text repeats itself: 'Raise an invoice in a WorkStream for the buyer to pay. Raises an invoice in one WorkStream,' and the confirmation point is restated twice. Redundancy costs it 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?

For a no-output-schema write tool, the description covers the key things an agent needs: what side effect occurs (buyer is asked to pay), the confirmation requirement, and auth needs. Given annotations already carry the safety profile, this is largely complete.

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%, so all three parameters (workstream_id, amount, description) are already documented in the schema. The description only lightly reinforces that amount and description are passed through and that the workstream is a single one, adding little beyond the schema baseline.

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 and resource ('Raise an invoice in a WorkStream') and scopes it to a single WorkStream for the buyer to pay, which is clear and distinct from sibling tools like create_offer or send_proposal. It does not explicitly name or contrast with those siblings, but the purpose is 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?

Gives meaningful operational context ('By default you confirm each call; you can switch that off') and a prerequisite (API key with app access), plus an external-reach warning to confirm with the user. However, it never states when to prefer this over alternatives such as create_offer, so usage is implied rather than fully framed.

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