update_contact

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

With no annotations provided, the description discloses the key behavioral trait of partial updates. However, it omits other behaviors such as permissions required, idempotency, or what happens when contact_id is invalid. More detail would improve transparency.

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 extremely concise with two sentences: one for purpose and one for usage hint. No unnecessary words, well-structured for quick comprehension.

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 simple parameters and existence of an output schema, the description covers the basic purpose and partial update behavior. However, it lacks context about error handling, validation, and side effects, making it only moderately complete.

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?

The input schema has 0% description coverage, so the tool description must compensate. The description only implies that the optional fields (email, first_name, etc.) are the ones to update, but does not explain any constraints (e.g., email format, required length). The parameter semantics are minimally conveyed.

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 contact', and the note about 'Only provide fields you want to change' further clarifies the partial update behavior. This distinguishes it from create_contact and delete_contact among siblings.

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 a usage hint ('Only provide fields you want to change') but does not explicitly state when to use this tool versus alternatives like create_contact or delete_contact. There is no guidance on context or prerequisites.

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