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

Annotations already declare destructiveHint=false and openWorldHint=false, and the description adds real context: the slug is refreshed as a side effect, the old name is retained as a former_name alias by default, the operation is a 'bounded mutation', it costs $0.10 and needs an API key. The 'Dayze is the context layer' line is vague filler, but the side-effect disclosure is genuinely useful beyond the annotations.

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-loaded with the action and its main side effect, then the routing rule, then operational notes. Mostly tight, but 'Dayze is the context layer — bounded mutation only' is promotional padding that does not help an agent invoke the tool.

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 an output schema present the description needn't explain return values, and the annotations cover the safety profile. What it supplies — alias retention, slug refresh, cost, auth — is close to sufficient; the only real gap is not distinguishing itself from the alias/update_person siblings that a caller would weigh against it.

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 only 40%, and the schema leaves preserve_old_name_as_alias undocumented — the description usefully supplies its default ('By default preserves the old name as a former_name alias'). It says nothing about request_id/idempotency_key beyond what the schema already states, so it only partially compensates for the coverage gap.

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?

Names a specific verb+resource pair ('rename a CRM contact's canonical name') and states the secondary effect ('refresh slug'), which is more than a restatement of the tool name. It also differentiates itself from the create+merge path, so an agent can place it relative to siblings like merge_people without opening a 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?

'Prefer this over create+merge for spelling fixes' is an explicit routing rule naming the alternative and the condition that selects it. However it is silent on the neighbouring alias tools (add_person_alias, update_person_alias, update_person), so an agent still has to guess whether a name change belongs here or in those.

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