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

Annotations only indicate readOnlyHint=false, so the description carries the burden of behavioral disclosure. It reveals the permission model, role priority rules, and leadership transfer restrictions, which go well beyond the annotation. However, it doesn't mention potential side effects or error conditions (e.g., what happens if a player is not a member), which would add further transparency.

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 a single sentence with a parenthetical block of important details. It front-loads the core action and packs permission rules and role list into a concise but dense structure. It could be slightly better organized with line breaks, but it 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?

With no output schema, the description should explain the operation's meaning and constraints, which it does thoroughly (permissions, role priorities, leadership transfer). It doesn't describe the return value or further edge cases, but for a 3-parameter tool with full schema coverage, the provided context is sufficient for an AI to select and invoke it correctly.

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 baseline is 3. The description adds meaningful extra semantics: player_id accepts a player ID or username, and role_id values are enumerated with an additional rule about leader transfer. This enhances understanding beyond the schema's own property descriptions.

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 uses a specific verb ('Promote or demote') and resource ('a faction member'), making it immediately clear what the tool does. It also distinguishes from sibling tools like faction_kick (removing a member) and faction_edit_role (editing role definitions) by focusing on assigning roles to members.

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 provides clear context on when to use the tool: leader can change any member's role, members with Promote permission can assign roles below their own priority, and only the leader can transfer leadership. It doesn't explicitly name alternatives, but the permission rules effectively define the appropriate usage boundaries.

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