update_dm_message

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

The description adds significant behavioral context beyond the annotations, including how the 'dm' parameter accepts either an ID or display name and that name resolution is limited to one-to-one DMs with the authenticated account. This clarifies parameter behavior without contradicting the idempotentHint=true annotation.

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 concise with two sentences that efficiently convey purpose, parameter details, and constraints. Every sentence adds value and there is no redundancy.

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 tool's three parameters and an existing output schema, the description is fairly complete. It covers the key parameter behavior and modification constraint. However, it could mention potential error cases (e.g., non-existent message) or authentication requirements.

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?

The description adds meaning for the 'dm' parameter by explaining its dual acceptance (ID or display name) and resolution behavior. The 'body' parameter is implicitly described as the only modifiable field. However, the 'messageId' parameter lacks any explanation beyond the trivial schema description.

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 'Update a direct-message message', identifying the specific verb and resource. It distinguishes from sibling tools like delete_dm_message and send_dm_message, and adds the key constraint that only the body can be modified.

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 clear context on usage, noting that only the body can be modified, which helps the agent understand scope. However, it does not explicitly state when not to use this tool or compare it to related tools like update_channel_message.

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