update_contact

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

With no annotations, the description carries the burden of behavioral disclosure, and it does disclose the most important trait: updates are merged rather than wholesale replacement. However, it does not state whether an unknown id is an error, whether the contact is created if absent, what response is returned, or what permissions are needed.

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 two short sentences with no filler, and the key behavioral caveat—merge semantics—is front-loaded after the action. Every sentence adds 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?

For a 4-parameter tool with a nested attributes object, no output schema, and no annotations, the description leaves important context unstated: the required id is not mentioned, the meaning/effect of attributes versus top-level fields is unclear, and return/error behavior is absent. The merge note is useful but not sufficient for fully correct invocation.

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 0%, and the description does not explain id, first_name, last_name, or the attributes object beyond the generic merge behavior. An agent must infer from field names and the nested object schema what each parameter does, so the description does not compensate for the missing schema descriptions.

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 first sentence 'Update a contact' names a specific action and resource, and the verb distinguishes it from sibling contact operations like add_contact, get_contact, and delete_contact. The follow-up about merging adds semantic precision, though it does not explicitly contrast with any sibling.

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 gives no guidance on when to choose update_contact over alternatives, nor does it mention prerequisites such as first retrieving an existing contact. The merge note implies a partial-update workflow, but it never says 'use this instead of delete+add' or 'use get_contact first to see existing fields'.

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