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

With no annotations, the description carries the full burden and does supply the authorization requirement (owner/admin only) plus two hard guardrails (no targeting the owner, no promoting to owner). It omits what happens on a rejected call, whether the change is audited/notified, and whether it is idempotent.

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 short sentences, zero filler, with the action front-loaded and the constraints following immediately. 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 3-param mutation tool with no annotations and no output schema, the description covers purpose, permission gate, and the two most dangerous edge cases. It is nearly complete; only failure/idempotency behavior is unaddressed.

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 the schema already documents board_id, user_id, and the role enum. The description reinforces the role restriction ("cannot promote anyone to owner") but adds no syntax, format, or lookup guidance beyond what the schema states; 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?

The description states a specific verb and resource ("change an existing board member's role") with the scope qualifier "existing" that separates it from add_board_member/remove_board_member/invite_board_member. An agent can identify this as the role-mutation tool without opening the 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?

It gives clear preconditions and exclusions: owner/admin only, cannot target the board owner, cannot promote to owner. It does not name a sibling alternative (e.g. use add_board_member to invite, transfer_board_ownership for ownership changes), so it falls short of explicit when-not/alternative routing.

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