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

Annotations declare destructiveHint=true, which would otherwise suggest permanent removal; the description usefully corrects that by disclosing it is a server-side soft-delete and describing the observable effect (disappears from mDM_list for both parties). It omits reversibility/restore path, permission requirements, and error behavior when the message isn't yours.

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 with no filler; the action and its constraint are front-loaded, and the soft-delete consequence follows as supporting detail.

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 one-parameter delete with no output schema and annotations covering the safety profile, this covers what the agent needs: which id, whose message, and what deletion actually means. Remaining gaps are minor (undo capability, failure modes).

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 100% and the single parameter is already documented as coming from mDM_list, so the description's '(from mDM_list)' adds provenance but no new syntax or format detail. Baseline 3 applies since the schema does the heavy lifting.

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 (delete), resource (direct message), and a scope constraint (one you sent) identified by message_id. An agent can immediately distinguish this from mDM_edit (modify) and mDM_list (read) 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?

Points to mDM_list as the source of valid message_ids, which is the key prerequisite for calling it. It also implicitly excludes deleting others' messages via 'you sent', but never names an alternative for editing or handling received messages, so it stops short of explicit when-not guidance.

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