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

The description discloses traits the annotations don't: the upsert semantics ('a member already assigned gets the new role'), the consequential side effect that assigning PRIMARY replaces the current primary, and the required permission level. That is exactly the extra context an agent needs before a non-destructive but state-changing call.

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 clauses, front-loaded with the core action and each carrying a distinct fact (roles, upsert, primary replacement, permission). No filler or repetition.

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?

An output schema exists, so return values needn't be explained, and permissions and mutation side effects are covered. The only gap is the undocumented firm_id parameter and the lack of guidance on where to obtain member IDs.

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 0%, so the description must compensate. It defines the meaning and allowed values of the role parameter, but says nothing about firm_id (which has a default of empty and is ambiguous), nor what client_id/member_id must reference. Partial compensation only.

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+resource ('Assign a firm member to a client') and enumerates the three valid roles, so the action is unambiguous. It doesn't explicitly contrast with siblings like get_client_team, but no sibling overlaps enough to create confusion.

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 states the prerequisite ('Needs the OWNER or ADMIN role in the firm') and implies when to use it (adding/adjusting a client's team), but it never names alternatives or exclusions. An agent gets context but no routing guidance against related tools.

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