start_session

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

No annotations are present, so the description carries full responsibility for disclosing side effects. It fails to mention prerequisites (e.g., whether a QR code is needed), idempotency, or what happens if a session with the same ID already exists. This is a minimal statement without behavioral depth.

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 sentence that is direct and contains no filler. It is appropriately sized for a tool with one well-documented parameter.

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 annotations and no output schema, and the description does not explain the expected outcome of starting a session or how it fits into the session lifecycle (e.g., needing to get a QR code). This leaves the agent with insufficient context to fully understand the 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?

The input schema has 100% description coverage, with the sessionId parameter fully documented including its default value. The description adds no information about parameters, so the baseline of 3 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 uses the specific verb 'Initialize' and clearly identifies the resource as a WhatsApp session connection. The word 'new' distinguishes it from sibling tools like get_session_status, get_session_qr, and logout_session, which operate on existing sessions.

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 is provided about when to use start_session versus alternatives like get_session_status or logout_session. The description only states what the tool does without any context for selection.

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