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

Annotations already declare readOnlyHint=true, idempotentHint=true and destructiveHint=false, and the description is consistent with them by saying it "opens nothing by itself." It adds genuine value in describing the return content (step-by-step screens, buttons, fields), though it does not describe the exact response shape or how long the guidance is. With annotations carrying the safety profile, this is solid but not exceptional added 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 core behavior is front-loaded in the first two clauses, which is good. But the long paragraph about e-conomic's REST API, AppSecretToken and AgreementGrantToken takes up roughly half the text and is tangential background rather than an instruction for invoking this tool — it reads like app-guide material.

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 read-only guidance tool with no output schema, the description covers what it returns, that it has no side effects, and what to do next with the browser tools. An agent has enough to call it correctly and use the result. It would be stronger if it stated what to do if the browser session is not already open on e-conomic.

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 there is nothing for the description to disambiguate and the baseline of 4 applies. The description correctly implies no input is needed, since the guidance is derived from the user's own e-conomic account context.

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 names a specific verb and resource ("Book invoice in the user's own e-conomic account") and then corrects the natural reading by stating it "Returns how to do it in e-conomic step by step (screens, buttons, fields) and opens nothing by itself." That makes clear it is a guidance tool, not a mutation tool, which is the key distinction from siblings like e_conomic_create_draft_invoice. It never explicitly contrasts itself with those siblings by name, so it stops short of a 5.

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 a clear usage sequence: call this first, "then do it with the cotlet_browser_* tools in the user's e-conomic Cloud Browser." It also implies there is no direct API route (only via a developer agreement), which steers the agent away from an impossible path. However, it never says when to prefer e_conomic_create_draft_invoice, e_conomic_create_entry, or cotlet_app_guide instead, so the sibling-selection guidance is only implied.

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