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

Annotations only declare readOnlyHint=false, so the description does useful work: it discloses that an empty string clears a field and that an empty `values` object turns the mutation tool into a field-listing call. It stops short of saying whether omitted fields are preserved or replaced, which matters for a partial-update 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?

Three tight sentences: what it saves, how the parameter works including the clear and list cases, then the sibling exclusion. The routing caveat is placed last and nothing is redundant.

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?

With no output schema, the description correctly compensates by describing what the listing mode returns (id, type, allowed options, current value). Combined with the clear-value semantics, an agent has everything needed to call it in either mode.

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 the baseline is 3, but the description adds real semantics the schema lacks: field_id -> value mapping is restated, empty string clears a field, and empty `values` lists all fields with id, type, allowed options and current value. The list-mode behavior is not derivable from 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?

States a specific verb and resource ('Save facts ... into their profile fields') with concrete examples (birthday, city, role), and explicitly names the sibling update_my_profile for the fields it does not handle. An agent can distinguish it from that sibling without opening either 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 routes the agent: use update_my_profile for name, headline, timezone, website, LinkedIn URL or X handle, and use this tool for the remaining fields. It also defines the empty-values invocation as a discovery call, covering when to use it in read mode.

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