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

With no annotations, the description carries the full behavioral burden and does well: it discloses irreversibility ("for good"), the editKey authorization requirement, and the concrete downstream destruction (links break, guest names, RSVP answers, and images erased). It stops short of stating permission scope, rate limits, or whether deletion is recoverable via any admin path.

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 tight sentence that front-loads the destructive action, then the prerequisite, then the consequences. Nothing is wasted and ordering matches how an agent needs the information.

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 two-param destructive tool with no annotations and no output schema, the description covers the critical unknowns: permanence, the auth key, and exactly what data is lost. Only the meaning of the two parameters themselves is left thin.

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%, so the description must compensate, and it largely does not. "Needs its editKey" merely restates what the required array already declares and adds no meaning for what editKey is (an owner/auth token) or what id identifies. The id parameter is entirely unaddressed.

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?

States a specific verb and resource ("Delete a letter") with an added permanence qualifier ("for good"). The destructive verb makes it trivially distinguishable from siblings get_letter, update_letter, and create_letter without opening any schema.

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 when to use it (permanent removal) and states the "needs its editKey" prerequisite, but offers no explicit when-not guidance or alternative routing (e.g., "use update_letter to modify instead"). Usage context is inferable rather than stated.

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