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

Beyond the annotations (readOnlyHint=false, destructiveHint=false, openWorldHint=true) the description discloses irreversibility ('cannot be deleted from a thread afterwards'), edit scope ('only you can edit it'), notification side effects, the confirmation default, and the API-key/access prerequisite. This is exactly the extra behavioral context annotations cannot carry.

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 core purpose is front-loaded and most clauses (notification reach, irreversibility, confirmation) earn their place for a people-reaching write. The final API-key sentence is somewhat boilerplate and slightly dilutes an otherwise tight block.

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 3-parameter, no-output-schema mutation with openWorld and notification side effects, the description covers consequences, reversibility, confirmation, and auth requirements well. It could be more explicit about reply_to_id ordering, but nothing critical for a correct call 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%, so text/board_id/reply_to_id are already documented, giving a baseline of 3. The description adds a consequence of @mention (notification to mentioned people) that goes slightly beyond the schema, but adds no new detail on board_id format or reply_to_id semantics.

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?

It states a concrete verb+resource ('Comment card on a board, or a reply in a comment thread') and enumerates the two supported modes, so an agent can tell it produces a comment rather than a note card. It does not explicitly contrast itself with siblings such as milanote_add_note, so it stops short of full sibling differentiation.

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?

There is strong operational guidance ('By default you confirm each call', 'confirm with the user before each call'), which implies when extra care is warranted. However, it never names an alternative tool or the condition for choosing a plain note vs a comment, or reply-to vs top-level, leaving that to inference from the param description.

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