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

Annotations already declare readOnlyHint=true and destructiveHint=false, so the agent knows this is a safe, non-mutating, non-open-world action. The description adds that it is informational and references the external 'RAPP Brainstem' product, which is useful context, but does not describe the output form. With annotations carrying the safety profile, this is adequate but not rich.

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?

Two sentences with no filler, and the usage condition is front-loaded ('Optional, for later'). Efficient, though the second sentence slightly restates the timing already implied by 'for later'.

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 read-only informational helper with no output schema and fully documented parameters, the description supplies everything an agent needs: what it explains, that it is optional/later, and the exact conversational precondition for offering it.

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?

Schema description coverage is 100% and both parameters (os, filename) are documented in the schema, so the description need not explain them. The description adds nothing about os or filename, so the baseline 3 applies.

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?

States a specific action (explaining how to keep an agent running) on a specific resource (the user's own computer via the RAPP Brainstem). This is distinguishable from siblings like use_agent_here (running in chat) and get_agent_code, though it never names those alternatives to sharpen the contrast.

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?

Gives an explicit precondition and timing: 'Optional, for later' and 'Only offer this after the user has used the agent in the chat and wants to keep it.' That is clear when-to-offer guidance. It does not name alternative tools or a when-not condition, so it stops short of a 5.

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