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

Annotations are all false (no readOnly, no idempotency, no open-world), so the description carries the full burden. It discloses multiple behavioral traits: the user becomes owner ('Der Nutzer wird Besitzer'), the server auto-computes contiguous times from day start, parallel groups share time instead of summing, and the warning not to calculate times manually. This is rich context well beyond the uninformative annotations. No contradiction with 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?

The description is long but every paragraph is functional — no filler. It front-loads the trigger phrases and the critical time-computation warning before the template and parallel handling. For a 12-parameter tool with tricky timing and grouping behavior, the length is justified. It could be slightly tightened but nothing is wasted.

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 is complex (12 params, nested modules) with no output schema and uninformative annotations, so the description must do heavy lifting. It covers the hard parts well: time computation, template fidelity, parallel groups, ownership. The only gap is the return value/response of the creation call, which is never mentioned. Still, for the agent's decision to call it correctly, the description is substantially complete.

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 100%, so baseline is 3. The description adds genuine supplementary value: guidance to use von/bis from templates instead of calculating durations, using art='break' for pauses, carrying over arten/spalten for template fidelity, and the same 'parallel' name for simultaneous groups. These instructions go beyond the schema's property descriptions and help an agent use the parameters correctly.

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 ('Legt eine neue Session an') with the domain scope (Workshop, Seminar, Training). It clearly distinguishes from siblings by being the creation operation — siblings like session_aendern, modul_aendern, session_lesen are mutations or reads on existing sessions. The trigger phrases ('leg mir … an', 'plane einen Workshop', 'erstelle eine Session') make the purpose unmistakable.

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 trigger phrases telling the agent when to invoke this tool ('Nimm das bei...'). It provides clear usage context. It doesn't explicitly name alternatives or exclusion cases, but the creation-vs-modification distinction against siblings is implied strongly enough, and the trigger phrases are actionable.

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