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

Annotations already mark this as destructive and non-idempotent, but the description adds critical context beyond those flags: the invitation is an irreversible email, cannot be retracted, requires user-side permission that the agent cannot grant, and sending to a guessed address could reach a stranger. This is exactly the behavioral transparency an agent needs.

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 front-loaded with the core action, then uses a clearly marked WICHTIG block for critical constraints and closes with a practical 'ask first' rule. Every sentence carries operational value; 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?

For a 3-parameter mutation tool with no output schema, the description covers the important operational context: permission requirements, the response behavior on missing permission, irreversibility, and the need to avoid guessing emails. Combined with the full schema coverage and destructive/readOnly annotations, nothing essential is missing for safe invocation.

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 100%, and the schema already explains id, email, and rolle in detail, including the meaning of each enum value and the warning not to guess the email. The description repeats the role labels but adds no parameter semantics beyond what the schema already provides, so the baseline of 3 applies.

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 states a specific verb and resource: 'Lädt eine Person per E-Mail zu einer Session ein' with three role options. This clearly distinguishes it from sibling tools like modul_aendern, session_anlegen, or session_kopieren, which target different objects or operations.

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 gives explicit when-to-use guidance: only when the user has explicitly allowed invitations in Sessionario, and it explains the scope of whom the agent may invite. It also tells the agent what to do when permission is missing — pass along the response and do not retry — and advises asking the user when in doubt.

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