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

Annotations already declare readOnlyHint=false, idempotentHint=true, destructiveHint=false and openWorldHint=false, so safety is covered. The description adds genuine value with 'Applied to future Jacks', which tells the agent the change is forward-looking and not retroactive. However, it stays silent on the more consequential ambiguity: with eight optional parameters and none required, it never says whether omitted fields are cleared or preserved, nor whether the 'name' parameter upserts an existing profile.

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 the action front-loaded and the effect ('Applied to future Jacks') appended as a second, distinct clause. Nothing is redundant with the annotations or schema, and every phrase carries information.

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 eight all-optional parameters, no output schema and a write operation, the definition should resolve at least the partial-update question. Annotations cover idempotency and safety but not merge-vs-replace semantics, which is the one thing an agent most needs before invoking a save with a sparse payload. Otherwise the scope of what 'brand voice settings' covers is adequately framed.

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%, so every parameter is already documented in the schema and the baseline is 3. The parenthetical list mirrors a subset of the schema fields (tone, sample posts, avoid words, emoji/hashtag) but omits name, sign_off and allow_em_dashes, adding no syntax, format or interaction semantics beyond what structured data provides.

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?

The description uses a specific verb and resource ('Save custom brand voice settings') and enumerates the content domains it governs (tone, sample posts, avoid words, emoji/hashtag rules). It is clearly distinguishable from get_voice_profile by the verb 'Save', but the sibling is never named, so differentiation is implicit rather than 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?

Usage is only implied: the agent can infer this is the write counterpart to get_voice_profile and that settings take effect on future generations. There is no explicit when-to-use, no guidance on calling get_voice_profile first to inspect current settings, and no mention of whether this creates a new named profile or updates an existing one.

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