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

With no annotations, the description carries the full burden. It usefully discloses that the note is private and never delivered to the visitor, which is the key behavioral trait, but it says nothing about permissions, whether notes are append-only, ordering, or what the call returns.

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, front-loaded with the action and immediately followed by the visibility constraint. Nothing is redundant or padding.

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?

This is a mutation tool with no annotations, no output schema, and fully undocumented parameters. The description covers visibility but omits who can write notes, how the conversation is targeted via bot_id/session_id, and any side effects an agent would want before calling 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 all three required parameters. The description implies what 'note' contains but gives no meaning for bot_id or session_id, nor how to identify the target conversation, so it fails to compensate for the schema gap.

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 ('Add a private agent note to a conversation') and clarifies the visibility scope. It implicitly contrasts with the sibling send_agent_message by saying the note is never sent to the visitor, but it doesn't name that sibling outright.

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 'for other human agents working the inbox' clause hints at the internal-collaboration use case, so usage is inferable. There is no explicit when-to-use/when-not or named alternative such as send_agent_message or list_conversation_notes.

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