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

Annotations already declare readOnlyHint=false, idempotentHint=false, and destructiveHint=false, so the mutation and non-idempotency profile is covered structurally. The description adds genuinely useful context about an auth requirement (caller must be a member) and the api_key, but says nothing about the result of adding an existing member or any error behavior.

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, front-loaded with the action and followed by the two operational constraints. Every sentence earns its place with no 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 three-parameter mutation tool with annotations covering the safety profile and no output schema, the description covers the membership precondition and auth requirement. The only notable omission is the duplicate-member outcome, which is a minor gap rather than a blocking one.

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 room_id, to, and api_key are already documented in the schema, including the api_key fallback to the Authorization header. The description adds no parameter-level detail (e.g., format of 'to', room_id provenance beyond the schema's own note), so the 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: 'Add an agent to a team room.' This is clearly distinct from sibling tools like oids_create_room (creates rooms) and oids_send_room_message (posts messages), so an agent can route correctly 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 one concrete precondition ('The caller must already be a member'), which implies the usage context, but it never states when to choose this over alternatives (e.g., creating a room or messaging a room) or what happens if the user is already a member. Adequate but with clear gaps.

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