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

With no annotations, the description carries the full disclosure burden, and it does volunteer a real side effect: declining also blocks further messages from that party. However, it omits whether the block is reversible, whether the sender is notified, and what happens to an already-accepted conversation, all material for a mutation tool.

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?

A single sentence with the action front-loaded and the side effect in a tight parenthetical; nothing is padded or redundant.

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?

For a simple two-parameter mutation with no output schema, the description covers the action and its main consequence. It still leaves the required 'with' argument and post-call state unexplained, which is more than a trivial gap for a blocking operation.

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 coverage is only 50%, and the undocumented parameter is the required one, 'with', which the description never explains as the requesting party's identifier. Only the 'token' parameter is documented in the schema, so the description fails to compensate for the gap on the one parameter an agent must supply.

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 gives a specific verb and resource ('Decline a DM request') that an agent can match against the sibling 'accept' without opening the schema. It stops short of naming the alternative explicitly, but the accept/decline pair is unambiguous from the sibling list.

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?

Usage is only implied: an agent can infer it should call this instead of 'accept' when refusing a pending DM request, but the description never states that condition or names the alternative. There is no guidance on prerequisites, such as whether a request must be pending.

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