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

Annotations already convey write and destructive behavior (readOnlyHint=false, destructiveHint=true) and idempotence. The description adds context beyond annotations by explaining why the owner's role can't be changed—'ownership transfer is a dashboard action on purpose, since it is the one change that can lock the owner out.' This rationale helps the agent reason about safety without contradicting the annotations.

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?

The description is only two sentences, with the primary action stated first and the restrictive caveat immediately after. Every sentence earns its place: the first defines the action, the second clarifies a critical limitation and its rationale. No redundancy or 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 simple mutation tool with only two fully documented parameters and an output schema (not shown), the description covers all essential context: what the tool does, the allowed values, the owner restriction, and the reasoning behind it. An agent has enough information to invoke it correctly without further clarification.

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 userId and role are fully documented in the schema, including the enum values and the owner restriction. The description restates the role values ('admin or member') but adds no new parameter-level information. Since the schema already carries the semantic weight, the description provides no additive value, warranting the baseline score of 3.

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?

The description states exactly what the tool does with a specific verb and resource: 'Sets a member's role to admin or member.' It also distinguishes from siblings like remove_member and invite_member by focusing solely on role changes. The additional caveat about the owner's role clarifies a boundary, making it unmistakable what this tool is for and what it cannot do.

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 implicitly tells the agent when to use this tool (to change an admin/member role) and explicitly excludes ownership transfer, stating it is a dashboard action. It doesn't name alternative tools, but the exclusion is clear and specific enough to prevent misuse. A minor gap is not mentioning other exceptions, but the owner restriction is the critical edge case.

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