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

Annotations already declare the mutation profile (readOnlyHint=false, destructiveHint=true, idempotentHint=false), so the safety bar is lower. The description adds top-level partial-update semantics ('Anything left out stays') that the schema only states for the `kinds` field, but says nothing about required permissions, reversibility, or how the destructive hint interacts with a merge-style update.

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 short sentences, zero waste, with the operation and its merge semantics front-loaded. Nothing is padded.

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?

Adequate for a 6-param, deeply nested mutation with no output schema and full schema coverage, but thin given the tool's complexity: no mention of how to clear/reset a preference, no time-zone dependency note for quiet hours or digest, and no routing to the read or reset siblings.

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 description coverage is 100% and nested objects carry their own descriptions (channels per kind, quiet-hours day/time encoding, digest hour), so the schema does the heavy lifting. The description adds no per-parameter meaning beyond the blanket merge note; baseline 3 is appropriate.

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?

Specific verb + resource: 'Change the signed-in person's own notification preferences.' The self-scoping phrase 'signed-in person's own' usefully distinguishes it from update_team_notification_defaults and reset_my_notification_preferences, though no sibling is named 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?

No guidance on when to use this versus get_notification_preferences (read first?), reset_my_notification_preferences, or update_team_notification_defaults. Routing is only inferable from the name, which is a gap in a cluster of four notification-preference tools.

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