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

Annotations already indicate this is not read-only and not destructive, so the safety profile is partially covered. The description adds meaningful behavioral context: the need for an explicit confirmation step before applying changes, which is not encoded in the annotations and is important for an agent to invoke the tool safely.

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 concise sentence that front-loads the core operation and uses 'after showing... and confirming' to add critical process detail without verbosity. Every phrase earns its place.

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 tool has 11 parameters, nested objects, and a confirmation requirement, but the description does not explain how the confirmation flag should be set or how idempotencyKey is used. The output schema likely covers return values, but the description plus sparse schema coverage leaves gaps around parameter usage and safe invocation for a complex update operation.

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 only 36%, so the description carries a heavier burden for explaining parameters. It only hints at 'confirmed' through the confirmation workflow but does not explain contactId, idempotencyKey, tags, groupIds, customFields, title, email, notes, or phone semantics. The schema covers some fields, but the description adds little beyond that.

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 action ('Update') and resource ('a contact'), and adds a distinctive workflow requirement ('after showing the exact proposed changes and confirming') that distinguishes this tool from create_contact and delete_contact. It leaves no ambiguity about what the tool does.

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 explicitly establishes the key usage condition: the update should only be performed after proposed changes have been shown to the user and confirmed. However, it does not explicitly state when not to use this tool or name alternatives such as create_contact for new contacts or delete_contact for removals.

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