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

Annotations cover the write/idempotency profile, and the description adds substantial context beyond them: the auth requirement, that MCP cannot sign the message, and that it currently only returns guidance until an agent session duct exists. That last point is critical for an agent to avoid expecting a real mutation.

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?

Two compact, front-loaded sentences that prioritize the action, then the blocker. Slightly jargon-heavy ('agent session duct'), but no wasted text.

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 5-parameter write tool with no output schema and 40% coverage, the description covers the crucial auth and no-op caveats but leaves optOut and the wallet requirement unexplained. It is adequate but not thorough.

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 only 40%, but the description names name, emoji, and 'preset' avatar, partially compensating. It says nothing about optOut or the required wallet field (which the schema itself documents), so coverage remains incomplete.

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 ('Set display name / emoji / preset avatar') and even names the endpoint. It distinguishes itself from the sibling memeswap_set_avatar by qualifying 'preset avatar', though the boundary between the two tools remains slightly ambiguous.

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 reveals the precondition (wallet session bearer or signed profile message) and the fact that MCP cannot sign, which implies when the tool is usable. However, it gives no direct guidance on when to pick this over memeswap_set_avatar or what the caller should do about the signing gap.

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