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

Annotations already flag destructiveHint=true and idempotentHint=true, yet the description still adds non-obvious semantics: it only affects future threads, existing conversations stay open, leaving is not a block, and Separate groups never surface. These are consequences an agent could not infer from the annotations or schema.

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?

Four compact clauses with the primary action front-loaded and the alternative close behind it. Dense but every clause carries distinct routing or behavioral information; no filler.

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, single-param tool with no output schema, the description covers the safety-relevant edge cases (own group exclusion, retroactivity, non-blocking, hidden group types) that an agent needs before calling 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 coverage is 100%, and the single param description already covers the name/'from list_groups' semantics. The description's 'naming the group' merely reinforces the schema without adding format or resolution detail, so 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 ('Take the user off a Shared group'), and explicitly distinguishes the sibling it is not: 'never their own; use update_group with dissolve'. An agent can route between leave_group and update_group without opening either schema.

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?

Names the alternative (update_group with dissolve) and the condition that selects it, and states the activation condition 'Only on the user's explicit request, naming the group'. Both when-to-use and when-not-to-use are explicit.

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