get_last_interaction

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

No annotations exist, so the description carries the full burden. It doesn't say what happens when the contact has no messages (null, error, empty object), whether 'involving' includes group chats where the contact merely appears, or whether the read is scoped to synced history.

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 core sentence is front-loaded and appropriately short. The leftover Python docstring 'Args:' block is minor noise but not harmful.

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?

A read tool with no annotations and no output schema needs the description to explain the return shape, and it never does. An agent cannot tell whether it receives a message object, a list, or null when nothing is found.

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 coverage is 0% and the description only restates the parameter name as 'the JID of the contact to search for', with no JID format (e.g. user@s.whatsapp.net) or example. It adds almost nothing an agent could not infer from the schema title 'Jid'.

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 gives a specific verb and resource: 'Get most recent WhatsApp message involving the contact.' An agent can tell it apart from list_messages or get_message_context by the 'most recent single' framing, though the sibling distinction is only implied, never stated.

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?

No guidance on when to prefer this over list_messages, get_message_context, or get_contact_chats, all of which could plausibly surface messages for a contact. Nothing about prerequisites or exclusion cases.

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