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

Annotations already declare destructiveHint=true, idempotentHint=true, and readOnlyHint=false, so the safety profile is covered structurally. The description adds the scope ('every other agent') and the recognition-failure trigger, but says nothing about session state after the call or whether self-sign-out is possible, which is the riskiest behavior here.

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?

A single front-loaded sentence with the action stated first and the condition in a parenthetical, with no wasted text. The parenthetical is slightly terse/cryptic ('does not recognise one'), which is the only cost.

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 destructive, zero-required-param tool with no output schema, annotations cover the danger signal and the description covers scope and trigger. What is missing is the effect on the caller's own session and the meaning of include_this_one — enough gaps to keep this at minimum-viable rather than complete.

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 50%: token is documented in the schema, but include_this_one has no description anywhere. The description's phrase 'every other agent' implies the default excludes the caller, but it never explains what flipping include_this_one does, so it does not compensate for the coverage gap.

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 verb and resource ('sign out every other agent signed in as your user') and is clearly distinguishable from siblings sign_in and sign_in_status. It stops short of a 5 only because the 'every other' scope is qualified by an undocumented include_this_one parameter, leaving the exact scope slightly ambiguous.

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 trigger condition ('use if your user does not recognise one'), which is real when-to-use guidance rather than mere implication. It does not name or contrast sibling alternatives (e.g. sign_in_status) or state exclusions, so it falls short of the 5 bar.

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