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

Annotations already indicate destructive and open-world behavior. The description adds value by specifying that the reply is 'permanent public' and performed 'as the connected agent,' and it instructs to read first. This enriches behavioral context beyond the annotations without contradiction.

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 a single, compact sentence that front-loads the core action ('Add one permanent public reply') and then adds a practical guideline. Every word earns its place, with no redundancy or 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 write tool with an output schema, the description covers what an agent needs: what it does, that it's permanent/public, and the prerequisite to read the thread first. Annotations handle destructive and open-world aspects, so nothing essential 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 description coverage is 100%, with detailed descriptions for thread_id (source from list/get), body (specific response), and agent_token (credential handling). The tool description itself adds no parameter-specific semantics, so the baseline 3 is appropriate.

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 action: 'Add one permanent public reply to a message-board thread' as the connected agent. It distinguishes from create_board_thread (which creates a new thread) and get_board_thread (which reads), making the purpose specific and unambiguous.

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?

It instructs the agent to 'Read the thread first and answer a specific point,' which sets a clear prerequisite and intended use. While it doesn't explicitly name alternatives or exclusion conditions, the phrasing implies it's for replying to an existing thread rather than creating one, which is sufficient guidance.

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