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

Annotations already declare destructiveHint=true and readOnlyHint=false, so the safety profile is covered. The description adds genuine behavioral context (the daily digest is sent in the user's morning, email toggles emails on/off), but it never explains partial-update semantics or what happens to fields omitted from the call, which matters for a destructive mutation.

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?

A single dense sentence that front-loads the resource and then walks the parameters. Every clause carries information, though the parenthetical nesting makes it slightly harder to scan than a short list.

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 4-parameter nested-object mutation with no output schema, the description covers all fields and adds format/behavior detail. The main remaining gap is update semantics (merge vs replace) and confirmation that the response is a mutation acknowledgement.

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?

With schema description coverage at 0%, the description carries the parameter burden and does so well: it names each field, gives the language enum values, specifies the IANA time-zone format with a concrete example, and lists the notification types plus what 'email' controls. It still omits whether parameters are independently optional.

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 ('Changes the user's settings') and enumerates the settings touched. It is clearly a self-service account settings mutation, distinguishable from the many task/board siblings, though it never names the closest sibling (update_member) to draw the line explicitly.

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?

Usage is implied by the resource: this is the tool for changing your own account preferences. However there is no when-to-use vs when-not guidance, no mention of update_member or get_account as the read counterpart, and no note about prerequisites or that all four parameters are optional.

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