Create thread

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

No annotations are provided, so the description must carry full burden. It discloses the two modes of thread creation but does not mention required permissions, rate limits, or error conditions (e.g., what happens if the channel does not support threads). The schema describes optional parameters like slowmode_seconds and auto_archive_minutes, but the description does not explain their behavioral impact.

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 long, front-loaded with the core purpose, and every sentence provides essential information. There is 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 creation tool with six parameters and no output schema, the description covers the critical usage modes and channel type. It lacks details on return values, error handling, and prerequisites like permissions, but it adequately conveys the tool's functionality for an agent to select and invoke it correctly.

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%, so the schema already explains each parameter. The description adds key context by linking message_id to the 'branch from a message' mode and omitting it for standalone. This clarifies the primary semantic distinction beyond the schema. However, it does not elaborate on other parameters like slowmode or name.

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 ('Start a thread') and resource ('from an existing message, or as a standalone thread'). It specifies the usage conditions with 'Pass message_id to branch from a message; omit it for a standalone thread', which differentiates the two modes and effectively distinguishes this tool from siblings like 'archive_thread' or 'list_threads'.

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 explicit guidance on when to use message_id versus omitting it for standalone threads. It mentions channel type ('text/forum channel'). However, it does not explicitly state when NOT to use the tool or mention alternatives, but given the sibling list, no other tool creates threads, so this is sufficient.

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