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

Annotations already convey that the operation is not read-only, not destructive, and idempotent. The description adds useful context about public threads being shareable via URL, which is a behavioral consequence. However, it doesn't detail other effects like reversal or immediate propagation, but given the annotations, the baseline bar is met.

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 two sentences, front-loaded with the primary action, and contains no fluff. Every sentence serves a purpose: stating the action and clarifying a prerequisite.

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 two-parameter setter with full schema coverage and an output schema, the description is complete. It provides the core behavior, the prerequisite, and a practical implication (URL sharing), without requiring excessive detail.

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?

The schema already covers both parameters with descriptions, so baseline is 3. The description adds meaning by linking is_public to the public/private states and clarifying that session_id comes from a previous debate session, which reinforces and enriches the schema's descriptions.

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's action: 'Set a thread as public or private.' It identifies the specific resource (thread visibility) and the two possible states, and adds the contextual note that public threads can be shared via URL. This clearly distinguishes it from sibling tools like get-thread-link.

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 implies usage when you need to change a thread's visibility, and it specifies that session_id must come from a previous debate session. However, it does not explicitly mention alternatives or when not to use this tool, such as referencing get-thread-link for retrieving the link.

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