contacts_update

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

With no annotations, the description carries full burden but only states 'Update an existing contact' without disclosing behavioral traits like partial vs full update, error handling, authorization needs, or side effects. This is insufficient for an agent to use the tool correctly.

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 very concise (4 words, one sentence) and contains no filler. However, it is so brief that it omits useful details, making it slightly less than optimal for a highly informative definition.

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 tool has 13 parameters and no output schema, the description is too minimal. It does not explain the update behavior (e.g., partial vs complete replacement), return values, or what happens if the contact ID doesn't exist. The description is inadequate for a tool with 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?

All 13 parameters have descriptions in the input schema (100% coverage), so baseline is 3. The description adds no extra meaning beyond the schema. Thus, it neither improves nor degrades 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 'Update an existing contact' clearly states the verb (update) and resource (contact). It distinguishes from siblings like contacts_create, contacts_delete, contacts_get, and contacts_list, making the tool's purpose unambiguous.

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 explicit guidance on when to use this tool versus alternatives. It does not mention when not to use it, prerequisites, or recommend siblings for other operations.

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