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

Annotations already declare readOnly/idempotent/closed-world, but the description adds genuinely new facts: the Lab is a free local app on Windows/Linux reachable at 127.0.0.1, and this call starts no computation, checkout, or external navigation. That last clause is important for a 'handoff' tool whose name might suggest launching something, and it is not derivable from annotations.

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?

Three sentences, front-loaded with the routing constraint, and each sentence carries distinct information (identity, where the proof runs, what is returned, what is not triggered). Mild deduction for the all-caps slogan and the 'free local app' marketing aside, which consume space without adding invocation guidance.

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 an output schema present and zero parameters, the definition supplies everything an agent needs: the routing constraint, the return contents, and an explicit statement that no computation or external navigation occurs. The agent can call it correctly and understands why sibling tools cannot substitute.

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; baseline 4 applies. Nothing in the text misleads about inputs.

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 concretely what the tool returns: the version served by /download and the Lab's real MCP path starting with start_here. It also distinguishes itself decisively from every sibling by declaring that no tool on this server opens a seal. The only weakness is that the action itself is framed indirectly (a 'handoff') and leads with a slogan rather than a verb+resource phrase.

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 strong negative rule — no server tool opens a seal, the proof runs in the desktop Lab — which effectively routes the agent away from every sibling when a verdict is required. It does not state the positive trigger explicitly (e.g. 'call this when the user asks for a sealed verdict'), leaving that inference to the agent.

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