reply_to_thread

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

No annotations are provided, so the description carries full burden. It states creation and immediate publication, which is transparent enough for a simple mutation. However, it does not disclose potential consequences (e.g., permanent visibility) or authorization requirements.

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 sentence that is front-loaded with the core purpose, followed by additional detail. No unnecessary words.

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?

With no output schema and no annotations, the description does not cover return values, error handling, or success indicators. For a creation tool that publishes immediately, more context about the result would aid the agent.

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 input schema covers 2 of 3 parameters with descriptions (thread_id and text), but reply_control lacks description. The tool description adds no extra information about any parameter, leaving the enum parameter unexplained.

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 'Post a reply to a Threads post' and 'Creates and immediately publishes a text reply,' specifying the verb, resource, and action. It distinguishes from sibling tools like create_text_post or manage_reply, which handle different operations.

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 use for replying to a thread, but does not explicitly state when to use this tool versus alternatives (e.g., use create_text_post for new posts, or quote_thread for quoting). No exclusions or context are provided.

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