Merge contacts

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

Beyond the destructiveHint annotation, the description reveals crucial behavioral details: dry-run by default, the need for confirm:true to execute, and that references from the losing contact move to the winner. This adds significant transparency about the operation's 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 extremely concise, with two sentences covering purpose, key parameters, dry-run behavior, and destructive nature. Every word earns its place, and the structure front-loads the core action.

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 description is complete for a straightforward merge tool, given that the schema documents all parameters and the annotations cover safety. It explains the reference transfer and dry-run, though it does not describe the output format or mention auditUser, which is acceptable since the schema covers auditUser.

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 already has 100% coverage with clear descriptions for each parameter. The description adds extra semantic context by explicitly linking winning and losing contact IDs to the merge operation and explaining the confirm flag's purpose, going just beyond the schema baseline.

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 tool's function: merging two duplicate contacts, with specific roles for winning and losing contact IDs. It uses specific verbs and resources, distinguishing it from sibling tools like update_contact or create_contact.

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 clear context for when to use the tool (when there are duplicate contacts) and explains the dry-run behavior. However, it does not explicitly mention alternatives or when not to use it, so it falls short of a 5.

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