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

Annotations only declare readOnlyHint/openWorldHint; the description adds substantial behavior beyond that: trainer notes, 'zusatz' and 'nachbereitung' appear only if the user may edit the session, attachments expose name/size but not content, and it explains block/parallel field semantics plus the recomputation pitfalls.

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?

Front-loads the return-value summary, then moves to conditional fields, attachments, and block/parallel arithmetic. It is long, but nearly every sentence conveys domain semantics the agent cannot infer; only the arithmetic aside is marginally redundant since 'dauer_minuten' already exists per day.

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?

No output schema exists, so the description must document the return shape, and it does so thoroughly (top-level fields, per-module fields, block and parallel sub-structures, conditional fields). An agent has everything needed to call it and interpret the response.

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% and there is a single 'id' parameter, so the schema already carries the parameter. The description still adds provenance ('Die ID kommt aus sessions_suchen'), which is useful but not deep syntax detail, so slightly above the baseline 3.

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?

States a specific verb (return/read) and resource (a full session), then enumerates what 'fully' means: all days, modules with time/duration, goal, content, material, and parallel subgroups. This clearly separates it from the sibling sessions_suchen, which only finds 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?

Gives explicit routing ('Die ID kommt aus sessions_suchen'), names the alternative for a related task ('hinzufügen kannst du mit anhang_hinzufuegen'), and states a non-obvious re-invocation rule: call it again after every change before touching the next module because module 'nummer' shifts.

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