Update Person Alias

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

Annotations already declare readOnlyHint=false, destructiveHint=false, and openWorldHint=false, so the description is not required to restate those. The description adds the cost ($0.05) and API key requirement, which are useful behavioral context. However, it does not disclose whether the update is partial or full replacement, whether missing fields are cleared, or what happens if the alias does not exist.

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?

The description is a single sentence that front-loads the core action and fields, with the cost and auth requirement appended compactly. It is appropriately sized for a simple update tool, though it could add a brief note about idempotency without becoming verbose.

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?

The tool has an output schema, so return values are covered elsewhere. The description covers the core action, cost, and auth, but it lacks guidance on idempotency keys (request_id/idempotency_key), partial-update semantics, and error behavior for nonexistent aliases. For a mutation tool with 7 parameters and low schema coverage, this is a moderate gap.

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 only 29%, so the description must compensate for undocumented parameters. It names three of the seven parameters (alias_kind, source, display) but does not explain the semantics of person_id, alias, request_id, idempotency_key, or alias_display. The description adds some meaning for the three named fields but leaves the rest to the schema, which is mostly undocumented.

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 states a specific verb ('Update') and resource ('existing alias') and names the fields being updated (alias_kind/source/display). It is clear enough to distinguish from add_person_alias and remove_person_alias, though it does not explicitly name those siblings.

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?

The description implies usage for updating an existing alias, and the sibling list includes add_person_alias and remove_person_alias, which an agent could infer as alternatives. However, there is no explicit when-to-use guidance, no mention that the alias must already exist, and no exclusion of when to use add/remove instead.

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