note

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

The description explicitly discloses the key behavioral trait: 'Reopens the thread: a note on an idle OR closed thread revives it to active. Closed is not terminal.' This is critical side-effect information that goes beyond basic functionality. No annotations are present, so the description carries full burden and meets it excellently.

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 front-loaded with the main purpose and uses a clear structure with paragraphs for parameter details and behavioral context. Every sentence adds value, though it could be slightly more terse without losing information.

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?

Given the tool's simplicity and the presence of an output schema, the description covers purpose, parameter guidance, and behavioral transparency adequately. It does not discuss error conditions or prerequisites, but those are minor gaps for a note-adding tool.

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 0%, so the description must compensate. It provides detailed semantics for the 'kind' parameter with four valid values and their meanings. For 'thread_id' and 'content', the names are self-explanatory, and the description doesn't add further detail, but the tool's simplicity makes this acceptable.

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 'Add a note to a thread' with a specific verb and resource. It distinguishes the tool from siblings like close_thread and open_thread by focusing on adding content, not managing thread state. The explanation of note kinds (move, failed, insight, open_q) further clarifies its purpose.

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 provides strong usage context: 'Write terse, optimized for future-Claude' and explains that notes reopen closed threads, which guides when to use it. However, it does not explicitly state when not to use it or compare with alternatives like respond or open_thread.

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