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

Annotations are present (readOnlyHint=false, destructiveHint=false), so the description's additional permission prerequisites and the explicit statement that removal is out of scope add behavioral context beyond the structured annotations. It could mention idempotency or multi-member partial-failure behavior, but with annotations already declaring it non-destructive, the coverage is adequate.

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, no filler. The action set and the sibling exclusion are front-loaded, and prerequisites and removal routing appear in the final clause. Every sentence earns its place.

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 mutating participant tool, the description covers purpose, permissions, action mapping, and the sibling for removal. An output schema exists, so return-value behavior need not be spelled out; the remaining context an agent needs is present.

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%; each parameter already has clear descriptions including the exact action enum and members format. The description restates the action semantics but does not add materially new parameter-level meaning, so the baseline 3 is appropriate.

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?

Description opens with concrete verbs and targets: 'Add members... (action=add)', 'make members admins (action=promote)', 'make admins ordinary members again (action=demote)'. It explicitly names the sibling wa_remove_participants for removal, so an agent can disambiguate without opening schemas.

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 provides explicit prerequisites per action ('Adding needs the account to be a member... promote and demote need an admin') and explicitly instructs when to use the alternative: 'To remove members, use wa_remove_participants.' No ambiguity remains about when this tool is appropriate.

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