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

The annotations already declare readOnlyHint=true, idempotentHint=true, destructiveHint=false, and the description is consistent with them ('opens nothing by itself'). Beyond that, it adds real context: it discloses that the return value is instructional rather than an action result, and explains the absence of a public Invoice2go API as the reason browser automation is required.

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 behavior and follow-up are front-loaded and easy to extract, but the opening clause ('from ChatGPT, Claude or any AI agent') is filler and the closing API-availability note, including a dated verification stamp, is verbose for the value it adds. It is not padded enough to obscure the point, but it could be tightened.

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 zero-parameter, non-destructive tool with annotations covering the safety profile and no output schema, the description supplies the essential missing piece: that the result is procedural instructions and that execution happens through cotlet_browser_* tools. Nothing critical to calling it correctly is absent.

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?

The tool takes zero parameters, so the baseline is 4. The description correctly implies no input is needed and focuses on what the caller receives and what to do next.

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 explicitly states the output is a step-by-step guide ('screens, buttons, fields') and that it 'opens nothing by itself', which resolves the ambiguity in the name 'send_invoice'. It also names the follow-up tool family (cotlet_browser_*), though it does not differentiate from sibling helpers such as cotlet_app_guide or invoice2go_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?

It clearly states the next step (perform the send with cotlet_browser_* in the Invoice2go Cloud Browser), which is genuine usage guidance. However, it gives no explicit when-to-use-this-instead-of guidance versus the other invoice2go tools or the app-guide sibling, leaving the routing choice to inference.

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