WhatsApp Desktop Diagnostic Doctor

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

Annotations already cover readOnly=true, idempotent=true, and destructive=false, so the safety profile is set. The description adds valuable concrete behavioral content beyond that: it verifies five specific facets of the local Windows app (installed, running, CDP reachable, session active, DB ready), which tells the agent precisely what state the tool is inspecting without contradicting the annotations.

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?

A single, front-loaded sentence that opens with the general action, then immediately follows with the specific checks being done. Every clause adds detail; there is no filler or repetition.

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 no input parameters, annotations cover safety, and there is an output schema (context signals indicates it exists), so the description doesn't need to explain return values. The description's list of checks combined with the schema is enough to properly call the tool; no missing behavioral detail (e.g., Windows-only, connector names) is absent.

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 tool has zero parameters, so there is nothing for the description to add to the schema. Baseline for 0 parameters is 4, which is appropriate.

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 a specific verb ('performs') and a specific resource ('local WhatsApp Desktop application on Windows'), and then enumerates the concrete constituents of the health check it does: installation, process status, CDP connectivity, session, and database readiness. This makes it trivially distinguishable from the sibling chat/contact tools, which act on messages and metadata.

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 phrase 'preflight health check' directly signals an intended use-before-actions context, giving clear context for when an agent should invoke it. However, it doesn't explicitly name an exclusion or alternative (e.g., 'use when you suspect the app isn't ready' vs. 'just try send_message and see the error'), though such guidance is implied by the diagnostics angle.

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