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

Annotations already declare readOnlyHint=false, destructiveHint=false and idempotentHint=true, so the bar is lower, yet the description adds real value: archiving is explicitly not deletion and the conversation reappears when someone writes again, and 'gelesen' explains its effect on the unread counter. It does not cover permissions or return behavior, keeping it at 4 rather than 5.

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?

Three short, front-loaded sentences: purpose first, then each action, then the parameter source. Every sentence carries information. Minor deduction for the mojibake character ('—') in the middle of the text, which slightly harms readability.

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?

With only two required parameters, annotations present and no output schema, the description covers everything an agent needs to call it correctly: both actions, their effects, and chat_id provenance. Only permission/error behavior and the exact response shape are unstated, which is acceptable given the annotations.

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 would be 3, but the description meaningfully expands the enum parameter: the schema only says 'Was passieren soll' while the text spells out the exact semantics and side effect of each of the two values. It also reinforces chat_id provenance.

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 the resource (eine Unterhaltung) and defines both concrete operations ('gelesen' sets read state so the counter is correct; 'archivieren' hides it from the list) rather than leaving the vague verb 'aufraeumen' alone. It is clearly distinguishable from siblings like chats_ansehen or nachrichten_lesen, though the headline verb itself is generic.

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?

Each enum action is explained well enough to imply when to use it, and the description tells the agent where chat_id comes from ('aus chats_ansehen'). However, there is no explicit when-not guidance and no statement of when to prefer chats_ansehen or nachrichten_lesen instead.

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