Mark as read

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

Annotations already cover safety (not read-only, idempotent, non-destructive), so the description's real contribution is the external side effect: on iMessage the recipient may see a read receipt. That is exactly the kind of cross-party visibility an agent needs before calling. It stops short of saying whether all messages in the conversation become read or only the latest, and the 'may' hedge leaves platform behavior somewhat open.

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?

Two short sentences with the core action front-loaded and the caveat second. Nothing repeated from the title beyond the unavoidable verb phrase, and no filler.

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 simple one-parameter mutation with annotations covering safety and no output schema, the description is adequate but thin. It omits what the single parameter expects and what scope of unread messages is affected, which are the two remaining things an agent would want before invoking it.

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 description coverage is 0% for the single required parameter, so the description carries the full burden and does not meet it. It never mentions 'chat_id', its expected format, or how to obtain one; the only hint is that the target is a 'conversation', leaving the identifier semantics to inference.

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 ('Mark a conversation as read'), which is unambiguous and clearly distinct from siblings like get_conversation or list_conversations. It does not explicitly contrast itself with any alternative, but the operation is unmistakable.

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?

Guidance is only implied: the agent can infer you call this when the user wants a conversation's unread state cleared. There is no statement of when not to call it, no mention of prerequisites, and no named alternative (e.g., batch read-marking) despite a large sibling set.

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