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

Annotations already declare readOnlyHint=true, idempotentHint=true, destructiveHint=false, so the safety profile is covered. The description adds real value beyond that by disclosing the return shape (step-by-step screens/buttons/fields) and explicitly asserting 'opens nothing by itself', confirming no side effects occur. Remaining gaps are minor (latency, whether output depends on current browser state).

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 workflow sentence is front-loaded and useful, but the closing sentence about Amazing Marvin's public REST API and the absence of an official MCP server is informational filler that does not help an agent select or invoke this tool. The core content is one sentence stretched across a long run-on.

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?

With zero parameters and no output schema, the description carries the burden of describing what comes back, and it does so concretely (screens, buttons, fields). The main missing piece is how the target task is determined given the empty input schema, which leaves a small but real gap for an agent.

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 of 4 applies; there is no argument surface for the description to explain. Nothing in the description misleads about inputs, though an agent might wonder how the target task is identified given no parameters.

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+resource ('Mark task done in the user's own Amazing Marvin account') and immediately clarifies that the tool itself does not act but 'Returns how to do it in Amazing Marvin step by step (screens, buttons, fields)'. This resolves the ambiguity inherent in the name. It stops short of distinguishing itself from the other amazing_marvin_* siblings by name.

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 sketches a two-step workflow ('opens nothing by itself; then do it with the cotlet_browser_* tools in the user's Amazing Marvin Cloud Browser'), which implies when to reach for it. But it never states prerequisites (e.g., must the Cloud Browser already be open on a task?) or when to skip it, and it points at a wildcard family rather than a concrete starting tool.

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