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 behavioral burden. It only says 'Update an existing contact' and mentions Holded API v2, but does not explain whether updates are partial or full replacement, what happens to omitted fields, permissions required, or side effects.

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 short sentence with no wasted words, but it is under-specified rather than appropriately concise. It is front-loaded but lacks the structural detail needed for a complex mutation tool.

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 ten-parameter mutation tool with nested objects and no annotations or output schema, the description is far too thin. It omits update semantics, required-field behavior, and any operational context the agent would need beyond the schema.

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 all ten parameters are already documented in the schema, including the important code-vs-vatnumber note. The description adds no parameter-level meaning beyond the schema baseline, which warrants a 3.

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 states a specific verb and resource: 'Update an existing contact.' This clearly distinguishes it from create/get/list/delete siblings by operation, though it adds no explicit sibling differentiation beyond the verb.

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?

There is no guidance on when to use this tool versus alternatives, prerequisites, or what conditions must hold. The agent must infer that this is the mutation counterpart to create_contact and get_contact.

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