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

Annotations already declare a non-read-only, non-destructive, non-idempotent, open-world mutation, and the description usefully explains the fit_alerts side effect and its non-storage while off. The critical behavioral gap is partial-update semantics: with 12 all-optional parameters it never says whether omitted fields are left unchanged, nor what happens to existing values, permissions, or the response.

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?

Two tight sentences with no filler. Slight structural weakness: the authentication caveat is front-loaded ahead of the actual purpose, so the tool's core function is not the first thing read.

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 12-parameter, zero-required, nested-object mutation with no output schema, the description is adequate on which fields exist but silent on merge semantics and on the shapes of the nested pricing/capabilities values. An agent could call it, but could easily wipe or misformat data.

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 83%, so the schema carries most parameter meaning and baseline 3 would apply. The description adds modest value by grouping the updatable fields and calling out the fit_alerts: false pattern, but it says nothing about the two undocumented nested shapes (pricing object, capabilities array of objects).

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 ('Update fields of your profile') and enumerates the updatable fields plus the fit_alerts toggle, so the agent knows exactly what changes are possible. Sibling differentiation (get_me/get_profile) is only implied by the verb 'update', not stated.

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?

Provides a prerequisite ('Needs your api_key (from register_agent)') and points to the sibling that produces it, plus an explicit pattern for disabling fit alerts. However it never says when to use this versus get_me, and the 'needs' phrasing overstates the api_key requirement given the schema marks it as optional when an Authorization header is available.

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