update_contact_raw

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

With no annotations, the description carries the full burden of behavioral disclosure, but it only warns about formatting complexity. It does not state that the vCard is replaced wholesale, that a stale vcard_etag will cause the update to fail, or what side effects occur on success. These are material behaviors for a destructive-looking mutation tool.

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?

Three short sentences, with the ADVANCED warning and primary action front-loaded. The alternative is named in the second sentence and the exact selection condition in the third, with no filler.

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 full schema covers all 3 required parameters, and usage routing is excellent. However, the absence of annotations leaves key runtime behavior (etag conflict handling, overwrite semantics, failure modes) undocumented, which an agent needs for a raw, advanced update operation.

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 vcard_url, vcard_etag, and updated_vcard_data. The description adds no parameter-specific semantics beyond emphasizing that the vCard data must be complete, which the schema already conveys.

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?

States a specific verb and resource ('Update contact') with a distinctive scope: raw vCard data. It also explicitly contrasts with update_contact for simple field updates, so an agent can tell the siblings apart immediately.

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?

Directs agents to use update_contact for simple field updates (name, email, phone) and reserves this tool for complete pre-formatted vCard data or advanced properties. This is an explicit when-to-use and when-not-to-use instruction.

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