update_message

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

With no annotations, the description carries the full burden and does so richly: it discloses that the whole body is replaced with plain text, that @mentions cannot be added and existing ones are flattened to plain text, and that the tool is only available in Global cloud (not GCC/DOD). These are non-obvious behavioral constraints an agent could not infer from the schema.

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?

Front-loaded with the one-line purpose, then conditional parameter guidance, then caveats, all in a compact block. Every sentence adds distinct routing or constraint information with no waste.

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?

An output schema exists, so return values need no explanation, and the description covers the remaining gaps: authentication-relevant deployment scope, message-type applicability, and content semantics. Nothing needed to invoke the tool correctly 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 0% across 5 parameters, so the description must compensate – and it does, mapping parameter combinations to the channel-vs-chat scenario and clarifying that content is plain text. It stops short of describing edge cases such as empty or oversized content, so it is not fully exhaustive.

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 opens with a specific verb+resource ('Edit a message you sent'), and the scope is narrowed against siblings by stating it works on top-level channel messages and chat messages but not thread replies. An agent can distinguish this from send_channel_message, delete_message, or reply_to_channel_message immediately.

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 gives explicit conditional routing: team_id + channel_id + message_id for channel messages, chat_id + message_id for chat messages. It also states exclusions (thread replies unsupported), though it does not explicitly name the alternative tool to use for that case.

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