chat_post_ephemeral

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 the tool sends an ephemeral message, but does not disclose limitations such as rate limits, visibility constraints (user must be in channel), or what happens if the user is not in the channel. Minimal transparency.

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, which is concise and front-loaded, but it is too short to provide necessary context. It earns its place but does not fully cover the tool's functionality.

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?

Given the complexity (7 parameters, 2 required) and lack of annotations or parameter descriptions, the description is incomplete. It does not explain what 'ephemeral' means, how to use optional parameters like attachments or blocks, or what the output schema returns.

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%, meaning the JSON schema provides no parameter descriptions. The tool description adds no information about parameters (e.g., channel, user, text, attachments, blocks). This is a critical gap given the 7 parameters.

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 uses a specific verb ('Send') and resource ('ephemeral message') with scope ('to a user in a channel'). It clearly distinguishes from siblings like chat_post_message (persistent) and chat_me_message (as bot).

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 usage for sending ephemeral messages but does not explicitly state when to use this tool versus alternatives like chat_post_message or chat_update. No exclusions or when-not-to-use guidance provided.

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