update_contact

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

With no annotations provided, the description carries the full burden of behavioral disclosure, but it only says 'Update an existing contact.' It does not disclose mutation semantics, whether unspecified fields are preserved, how null values are handled, error behavior for nonexistent contact_id, or any permission requirements.

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 four-word sentence with zero waste and front-loaded intent. However, its extreme brevity sacrifices informational value, making it concise but not optimally helpful.

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?

Despite having a complete input schema and an output schema, the description omits critical behavioral context for a mutation tool: partial-update semantics, null-field interpretation, effects of updating 'unsubscribed', and failure behavior. The lack of annotations makes this a significant 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 100%, so the schema already documents all four parameters (contact_id, first_name, last_name, unsubscribed). The description adds no parameter-level meaning, landing at the baseline 3 for high-coverage schemas.

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 'Update an existing contact.' states a specific verb (update) and resource (contact), clearly conveying the action. The qualifier 'existing' subtly distinguishes it from the sibling create_contact, though it does not explicitly differentiate from the other contact-related tools.

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?

No guidance is given on when to use this tool versus create_contact, delete_contact, or get_contact. There are no exclusions, prerequisites, or alternative tool mentions, leaving the agent to infer usage solely from the name.

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