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

Beyond the readOnlyHint/idempotentHint annotations, the description discloses the key behavioral fact an agent needs: the tool performs no action itself and returns a procedural walkthrough, with the mutation happening later through browser tools. It also identifies the target account and environment (user's own Procountor account, Cloud Browser). The side note about Procountor's REST API not being switchable on adds rationale for the browser path, though it is not needed for invocation.

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 core scope and the follow-up instruction are front-loaded, which is good. However, the final sentence about Procountor's official REST API and its activation status does not help an agent decide whether or how to call this tool, and the "from ChatGPT, Claude or any AI agent" clause is filler. Roughly a third of the text does not earn its place.

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, no-output-schema tool, the description adequately conveys what comes back (step-by-step screens, buttons, fields) and what to do next. It does not explain how the target invoice is resolved without parameters, nor what happens if multiple unpaid invoices exist, leaving a real operational gap for a mutation-adjacent workflow.

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?

With zero parameters and full schema coverage there is nothing for the description to disambiguate, so the baseline of 4 applies. One useful detail is missing: since the schema takes no arguments, it is unstated how the tool identifies which invoice to approve (presumably from conversation context), which an agent might wonder about.

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 states a specific verb and resource ("Approve invoice") and immediately corrects the likely misreading by saying it "Returns how to do it in Procountor step by step... and opens nothing by itself." That distinguishes it from the cotlet_browser_* siblings that perform the actual clicks. It falls short of 5 only because the misleading name still requires a full sentence of clarification rather than a clean one-line scope statement.

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 gives an explicit two-step workflow: call this first to get the screens/buttons/fields, then carry it out with the cotlet_browser_* tools in the user's Procountor Cloud Browser. That is clear sequencing guidance. It does not explicitly say when NOT to use it versus procountor_list_unpaid_invoices or procountor_create_invoice, so no exclusion logic is present.

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