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

Annotations declare destructiveHint=true, and the description usefully clarifies that only passed fields change (v3.1 partial update) and names the underlying PUT /Contacts call. This adds real context against the scary destructiveHint, but there is no mention of permissions/auth, what happens to omitted fields' behavior at scale, or error handling.

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 core operation front-loaded and zero filler. Reasonably tight for the complexity involved, though the API-path sentence is only marginally useful to an agent.

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 19-parameter destructive mutation with no output schema, the description covers the important partial-update behavior but omits permission requirements, required-field emphasis, and any failure/return context. Adequate but with clear gaps.

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 74%, so most fields are self-documented and the baseline is 3. The description adds no per-parameter meaning beyond the general 'only passed fields change' rule, and never calls out the required contact_id or the custom_fields clearing semantics that the schema handles.

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 a contact'), and the resource name distinguishes it from the sibling update tools (update_lead, update_opportunity, update_organisation, update_task). It does not explicitly contrast with create_contact, but the verb makes the distinction obvious.

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 on when to use this versus alternatives (e.g., create_contact) or on prerequisites such as needing an existing contact_id. The 'partial update' note describes behavior, not usage context, so the agent gets no routing help.

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