Update contact

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

No annotations are provided, so the description carries the full burden. It discloses the requirement for CIVICRM_ALLOW_WRITES=true, which is a behavioral trait. However, it does not mention what happens on success, error, or if the contact is missing. For an update tool, this is minimally adequate but could be more transparent.

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 sentences long, front-loaded with the core purpose, and includes an essential requirement without any unnecessary words. Every sentence earns its place.

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?

Given the low complexity, 100% schema coverage, no annotations, and no output schema, the description is complete enough. It provides the purpose and a key prerequisite. It could mention return behavior but is not required per rules.

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 coverage is 100%, and the description adds value beyond the schema by explaining dot-notation for custom fields in the 'values' parameter. This helps the agent understand how to structure nested data, which the schema alone does not fully clarify.

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 'a single CiviCRM contact by id'. It distinguishes from sibling tools like civicrm_create_contact and civicrm_get_contact by specifying 'update' and 'by id'. The requirement for CIVICRM_ALLOW_WRITES=true adds specific context.

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 (to update a contact by id) but does not explicitly mention when not to use or provide alternatives among the sibling tools. It is clear for its primary use case but lacks exclusion guidance.

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