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. It implies a mutation but does not state whether partial updates are allowed, whether special permissions are required, or what happens when the contactId does not exist. The description is too sparse to inform the agent about side effects or error conditions.

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, concise sentence with no redundant words. It is appropriately front-loaded with the verb and object. However, it is perhaps too terse, though that is a completeness issue rather than a conciseness one. For the small amount of content it has, it is well-structured.

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 five parameters, no output schema, and no annotations, yet the description only offers 'Update a CRM contact'. This is completely inadequate for the agent to understand return values, update semantics, required fields, or edge cases. It fails to provide necessary context for a mutation tool of this complexity.

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 mentions no parameters at all. The schema lists five string fields, but the description fails to clarify any semantics such as which fields are commonly updated together or whether all fields are optional beyond contactId. The description adds no value to the parameter understanding.

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 clearly states the verb 'Update' and the resource 'CRM contact', making the tool's primary function evident. It distinguishes from siblings like create_contact and get_contact, though it doesn't provide additional context about which details can be updated.

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 provides no guidance on when to use this tool versus alternatives such as create_contact or add_contact_note. There is no mention of prerequisites, typical use cases, or conditions that would make an update necessary.

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