Update a contact

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

Annotations already communicate that this is not read-only, is idempotent, and is not destructive. The description adds the PUT endpoint and the 'existing contact' scope, but does not disclose whether the update replaces the whole contact or only supplied fields. It neither contradicts the annotations nor adds significant behavioral context beyond them.

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 short and front-loaded with the action. The first line repeats the tool title somewhat redundantly, but the second line adds specificity and the third line gives the HTTP endpoint, so there is minimal wasted text.

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 description is sufficient for a straightforward update operation, especially with schema details and annotations covering idempotency and destructive behavior. However, it does not clarify partial versus full update semantics or describe what the tool returns, and there is no output schema to fill that 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?

The description only reinforces that the update is by ID, which the schema already documents. The schema provides descriptions for the id, administration, and most contact body fields, so the moderate schema coverage carries most of the burden. The description does not add meaningful parameter detail beyond the schema.

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 and resource: 'Update an existing contact person by ID.' It clearly distinguishes this from create_contact and get_contact by emphasizing 'existing' and 'Update,' so an agent can identify the tool's purpose without opening the 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?

The description implies when to use the tool: to update a contact that already exists, identified by ID. However, it does not explicitly mention alternatives like create_contact for new contacts or get_contact for reads, leaving the usage routing partly to inference.

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