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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive, closed-world), so the description's added value is the result shape: header fields, "von_mir markiert eigene Nachrichten", and the default window "letzte 50, aelteste zuerst". That ordering and self-message flagging is behavior an agent cannot infer from 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?

Four short sentences, each carrying a distinct fact (what it returns, where chat_id comes from, default ordering, response flagging) with the primary purpose and the usage imperative front-loaded. No filler or redundancy.

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 correctly takes on the burden of describing return contents and the von_mir flag, which makes the tool callable and interpretable. The one gap is pagination: anzahl caps at 200 and nothing says how to reach older messages beyond the default window.

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 both parameters are already documented; the description adds provenance for chat_id ("kommt aus chats_ansehen oder benachrichtigungen") which tells the agent where to obtain a valid value. The "Standard: letzte 50" largely restates the schema's default, so it earns a 4 rather than a 5.

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 and resource ("Liest den Verlauf einer Unterhaltung") and enumerates what the response contains (post_id, Eintrag-Snippet, mit wem, mein_post), so an agent knows exactly what it gets. The closing line "Vor dem Antworten lesen" implicitly contrasts it with nachricht_senden, making the read-versus-write split obvious.

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 an explicit trigger ("Vor dem Antworten lesen — sonst schreibst du an etwas vorbei") and names where the required chat_id must come from (chats_ansehen or benachrichtigungen), which is real routing guidance. No explicit when-not-to-use case or named alternative tool, so it stops short of a 5.

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