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

The description discloses that list fields replace the entire list, which is a behavioral trait beyond what annotations provide. Annotations already indicate destructiveHint=true, so the description adds the specific list replacement nuance. However, it doesn't mention other side effects like whether scalar fields are partially updated or if all fields must be provided, leaving some uncertainty.

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 concise, a single sentence, and front-loads the action and the critical list replacement note. It is not verbose, but for a tool with many fields, it might be too terse. The structure is efficient, but it sacrifices completeness.

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?

The tool has a large schema and an output schema, but the description is minimal. It doesn't explain update semantics (e.g., partial vs. full update), return values, or error handling. The list replacement note is helpful but insufficient for a tool with this complexity. The agent would need to infer much from the schema, which is not fully covered by the description.

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?

The schema descriptions are comprehensive for each field, but the tool description adds only the list replacement behavior for list-type parameters (health_conditions, supplements). Since schema description coverage is 0%, the description carries some burden, but it doesn't explain individual parameter meanings. It adds value by clarifying list semantics, but not enough to fully compensate for the lack of coverage.

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 the action ('Update profile fields') with a specific resource, and it mentions a key behavioral nuance (list fields replace the whole list). It is specific enough to distinguish from read-only tools like get_profile, though it doesn't explicitly name alternatives. The purpose is clear but not exceptionally differentiated.

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 no guidance on when to use this tool versus alternatives. It doesn't mention prerequisites, conditions, or exclusions. The only usage hint is the list replacement behavior, which is about how the tool works, not when to use it. This is a significant gap for a mutation tool with many parameters.

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