threads_reply

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

Annotations indicate readOnlyHint=false (modifying), openWorldHint=true (creates), but provide no detail on flows. The description adds critical behavioral context: auto_publish behavior, the two-step requirement for media, and the race condition warning. This goes beyond annotations, though it could mention auth or rate limits.

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?

Two sentences, front-loaded with purpose, then key behavioral details. Every sentence earns its place with zero redundancy. Highly concise and structured.

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 tool with 5 parameters, 2 required, no output schema, the description covers the core reply functionality and the two distinct flows. It lacks details on return values or error cases, but given the tool's relative simplicity and the schema richness, it is adequately complete.

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% with decent descriptions, but the tool description provides extra context: the interaction between auto_publish and media type, the mutual exclusivity reminder, and the race condition note. This adds value beyond the schema, justifying a 4.

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 begins with a clear verb+resource combination: 'Reply to a Threads post or another reply.' It distinguishes from sibling tools like threads_get_replies (fetching) and ig_reply_to_comment (Instagram). The mention of text-only vs media flows further clarifies 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 explains when to use the single-step flow (text-only) vs two-step flow (media) and notes mutual exclusivity of image_url/video_url. However, it does not explicitly state when not to use this tool or compare directly to sibling publishing tools like threads_publish_text, which might cause confusion for agents.

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