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

The description adds key behavioral context beyond annotations by disclosing that there is no live email/SMS functionality and that the tool is a placeholder. It also includes cost context (2 MESH/call). Annotations declare readOnlyHint=false and destructiveHint=false, but the description's 'NOT YET IMPLEMENTED' warning is more informative and does not contradict them.

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 a single compact block with the critical 'NOT YET IMPLEMENTED' signal front-loaded)Skip — no filler. The parenthetical metadata is slightly extraneous but does not significantly hurt clarity.

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 placeholder with no output schema, the description covers the essential facts: unimplemented, no live sending, cost, and capability reservation. It does not specify what happens if invoked (e.g., no-op or error) or name alternatives, but the placeholder status makes this acceptable.

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, so the baseline is 3. The description adds no parameter-level guidance, and the schema's example payloads reference other tools (agent-brain, agent-memory), not this placeholder. The description could have clarified that the input payload is irrelevant or unused, but it does not.

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 states in its first sentence that this is NOT YET IMPLEMENTED and is a placeholder reserving a capability slot, and explicitly says no live email or SMS sending exists. This is unambiguous about what the tool currently is and clearly distinguishes it from actual messaging siblings.

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?

It clearly signals when not to use the tool: it is not implemented and has no live sending capability behind it. However, it does not name an alternative tool to use instead for email/SMS, so it stops short of full routing guidance.

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