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

Annotations already cover the safety profile (readOnly, idempotent, closed-world), and the description adds real value on top: it discloses that the tool never pushes updates and must be polled, what fields come back, and the unread-count escalation path. It does not mention pagination limits or ordering guarantees beyond 'letzte Nachricht', but the missing return schema is largely compensated.

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 sentences, front-loaded with the payload contents, then the polling caveat, then the escalation workflow – no filler. Minor deduction for the mojibake em-dash ('—') that slightly hurts 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 no output schema, the description carries the return-value burden itself and does so by enumerating the per-chat fields, plus it adds the crucial non-obvious fact that there is no push and the tool must be polled. Nothing an agent needs to select and invoke this tool correctly is missing.

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 the single parameter 'anzahl' is fully documented in the schema (1-100, default 30, newest first). The description adds nothing about it, so the baseline 3 applies – no deficiency, but no extra value either.

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 first sentence names a specific verb and resource ('Listet die laufenden Unterhaltungen') and enumerates exactly what each row contains (counterpart, post, mein_post flag, empty status, last message, unread count). This clearly distinguishes it from nachrichten_lesen/nachricht_senden, which it names as follow-up tools, though it never contrasts itself with chat_verwalten or benachrichtigungen.

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 operational guidance: there is no push mechanism, so poll it when the user asks whether anyone wrote or on a periodic basis. It also states the concrete branch 'Bei ungelesen_gesamt > 0: nachrichten_lesen, dann nachricht_senden mit chat_id', which tells the agent exactly which sibling to call next and in what order.

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