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

Annotations already declare the safety profile (readOnlyHint=false, destructiveHint=true, idempotentHint=true), so the description carries a lighter burden. It adds genuine context the annotations lack: authorization requirements (owner-only) and billing constraints (paid plan for both users). It does not note idempotency or what happens to an already-present member, leaving a small gap.

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 tightly-packed sentences: core action first, then prerequisites, then the alternative-tool redirect. No filler, and the most important behavioral constraint is front-loaded.

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 two-parameter mutation with no output schema, this covers action, authorization, billing prerequisite, and sibling routing. Only minor gaps remain (idempotency behavior on re-add, failure modes), which is why it falls short of a 5.

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% with both parameters documented as Team ID and User ID, so the schema does the heavy lifting. The description only restates 'user to add' and adds no format, syntax, or sourcing guidance beyond the schema. 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?

States a specific verb and resource ('Add a user to a team as a member') and distinguishes itself from the ownership-changing sibling by naming muninn_team_transfer_owner directly. An agent can tell it apart from muninn_team_invite and muninn_team_transfer_owner without opening any 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?

Explicitly states two prerequisites (caller must be the team owner; paid plan required for both parties) and names the alternative tool for the ownership case. When-to-use, constraints, and the routing alternative are all present with nothing left to inference.

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