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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, so the safety profile is covered. The description adds behavioral context beyond annotations: default limit (50), ordering (oldest first), and the inclusion of header fields. This is useful but not exhaustive; it doesn't describe potential edge cases or full response structure.

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 three sentences, front-loading the main purpose and then providing usage details and a warning. It is efficient and contains no filler, though it could be slightly tighter if the warning were integrated more directly.

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?

For a read-only tool with no output schema, the description adequately covers what is returned (header fields), the default limit and ordering, and the source of the chat_id. It also gives a usage directive. It doesn't mention error handling or pagination, but these are not critical for this simple read operation.

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 fully documented. The description adds minimal extra meaning—it mentions the default count and ordering (not in schema), but it largely repeats the chat_id explanation from the schema. The added ordering info is helpful, but the overall parameter semantics are already well-handled by the schema.

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 clearly states the tool reads a conversation history, listing specific header fields (post_id, entry snippet, with whom, my_post). It implies differentiation from siblings by noting chat_id comes from chats_ansehen/benachrichtigungen, which are list-type tools, though it doesn't explicitly name alternatives.

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 context: 'Vor dem Antworten lesen — sonst schreibst du an etwas vorbei' tells the agent when to use this tool (before replying). It also explains the chat_id source and default behavior, providing clear usage guidance without naming alternatives or exclusions.

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