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

With no annotations, the description carries the full burden. It discloses the return value, cost, and default-account behavior, but does not clarify partial vs. full update semantics (e.g., whether omitted fields are cleared or left unchanged). This is a notable gap for a mutation tool.

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 brief and front-loaded with the primary purpose, followed by essential usage details and return/cost info. Every sentence is informative with no fluff.

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?

Given the rich output schema and 100% parameter schema coverage, the description covers key dependencies and return value. However, it omits the critical update behavior (partial vs. full replacement), leaving a clear gap for an agent to act incorrectly.

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 coverage is 100%, so baseline is 3. The description adds value by explaining clerk_instance_id's role (target specific connection vs. default), which goes beyond the schema. Other parameters are already well-described in the schema.

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 clearly states 'Update profile fields for a Clerk user,' which specifies the verb and resource. It is distinguishable from siblings like clerk.update_user_metadata by focusing on 'profile fields,' though it does not explicitly name alternatives.

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 usage context by instructing to call clerk.get_connected_accounts first and explaining how to use clerk_instance_id. However, it does not mention when to choose this over alternatives, so it stops short of a 5.

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