messages_update

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

No annotations are provided, so the description carries the full burden of behavioral disclosure. While 'Update' implies a mutation operation, the description doesn't specify permissions required, whether the update is destructive or reversible, rate limits, error conditions, or what happens if the messageId doesn't exist. For a mutation tool with zero annotation coverage, this is a significant gap in 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 extremely concise at three words, with zero wasted language. It's front-loaded with the core action ('Update'), making it easy to parse. While brevity can lead to under-specification, in terms of structure and efficiency, this description earns full marks for getting straight to the point.

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 of a mutation tool with no annotations and no output schema, the description is incomplete. It lacks details on behavioral traits (e.g., side effects, error handling), usage context, and what the tool returns. The high schema coverage helps with parameters, but overall, the description doesn't provide enough context for safe and effective use by an AI agent.

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 input schema has 100% description coverage, with clear documentation for 'messageId' and 'message'. The description doesn't add any semantic details beyond what the schema provides (e.g., it doesn't explain the structure of the 'message' object or validation rules). Given the high schema coverage, a baseline score of 3 is appropriate, as the description doesn't compensate but also doesn't detract.

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 'Update an existing message' clearly states the verb ('Update') and resource ('an existing message'), making the basic purpose understandable. However, it doesn't distinguish this tool from sibling tools like 'messages_create' or 'messages_delete', nor does it specify what aspects of a message can be updated. It's adequate but lacks differentiation and specificity.

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 no guidance on when to use this tool versus alternatives. There are multiple sibling tools for messages (e.g., 'messages_create', 'messages_delete', 'messages_get'), but the description doesn't indicate when updating is appropriate, what prerequisites might exist (e.g., needing a valid messageId), or any constraints on usage. This leaves the agent without context for tool selection.

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