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

Annotations already declare destructiveHint=true and idempotentHint=true, so the safety profile is covered. The description adds genuinely useful behavioral context beyond that: the default is a broad, account-wide sign-out, so an agent knows the blast radius of omitting parameters. It omits consequences such as session/token revocation or the need to re-authenticate, keeping it from a 5.

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 sentence that front-loads the default behavior and then the two narrowing options. Every clause carries information; there is no filler or redundancy.

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 no output schema, zero required parameters, and annotations covering safety, the description supplies everything needed to invoke the tool correctly across all three modes. It could be slightly more complete by noting what a signed-out session implies (e.g., re-login required), but nothing essential for correct invocation is missing.

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%, so both parameters are already documented in the schema, including the omit-to-widen behavior. The description restates the same omission semantics without adding format, validation, or edge-case detail, 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 verb and resource ('Sign the user out') and immediately enumerates the three scope levels: all restaurants by default, one restaurant via clientId, one account via label. This clearly separates it from siblings like login and switch_account, which perform different session operations.

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?

The description gives explicit selection rules for each mode of use (omit both = everywhere; clientId = one restaurant; label = one account), which is effectively when-to-use guidance at the parameter level. It stops short of naming an alternative tool or a when-not-to-use condition, so it does not reach a 5.

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