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

Annotations already declare readOnlyHint and destructiveHint=false, so the safety profile is covered; the description reinforces this and adds genuinely new behavioral context — that a false has_profile is a legitimate empty state, not a failure, and that the three registers are semantically distinct. No return format detail, but annotations carry the safety burden.

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?

Front-loads the core definition of the resource, then handles the register semantics and the false-state case. Dense but each clause carries information; slightly long but no obvious waste.

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 compensates by listing the profile's components and explaining the empty-state behavior, which is what an agent needs to interpret a call. Complete enough for a single-optional-param read tool.

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 baseline is 3, but the description goes beyond the schema by defining each enum value's provenance (brand = website's voice, personal = founder's writing, imported = from a brief) and noting they do not sound alike — meaningful semantics the enum list alone doesn't convey.

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 (read/view) and resource (the structured voice profile) and enumerates exactly what it contains: tone, characteristic phrases, vocabulary, sentence style, and avoided patterns. An agent can distinguish this from siblings like set_voice_axes or record_voice_rule without opening any 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?

Gives clear usage context for the register parameter (omit for current, use 'personal' for founder posts) and clarifies the has_profile=false case as a valid answer rather than an error. It does not explicitly point to alternatives such as set_voice_axes for writing a voice, so it falls short of full when/when-not routing.

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