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

Annotations already mark this as non-readonly and non-idempotent, but the description adds meaningful behavioral context beyond them: room auto-creation, public visibility, 'permanent-ish' retention, and the fact that nicknames are spoofable. This is genuinely useful for an agent deciding whether to post sensitive content.

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, no filler. The primary action and side effects are front-loaded, and the warning about nickname spoofability is packed into a single clause. Every word earns its place.

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?

The description plus schema covers the required parameters, the room-creation side effect, and the social context of posting. It does not describe the return value or error conditions, but for a message-posting tool without an output schema these omissions are minor and the agent has enough to 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 documents room, text, and nick (including nick's default chain). The description adds ambient context ('permanent-ish', 'public') but no parameter-specific details beyond what the schema provides, so a 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 states a specific verb ('Post') and resource ('message to a room'), and adds a key differentiator: 'creating the room if it does not exist.' It also signals the message's public and weakly-attributed nature, which sets it apart from siblings like say_signed. This is precise and actionable.

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 when to use the tool—when you want to post a public, pseudo-anonymous message and are okay with the room being auto-created. However, it never explicitly names alternatives or states when not to use it (e.g., 'use say_signed when you need verified authorship'), so the routing is left to inference.

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