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

Annotations already declare write semantics (readOnlyHint=false, idempotentHint=false, openWorldHint=true), and the description adds genuinely useful context: the auth requirement and the fact that it returns guidance rather than performing the write. That last point is undercut by opaque jargon ('agent session duct') and no statement of what the guidance response actually contains.

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 short sentences with the action front-loaded and the constraint following, so it is scannable. The phrase 'agent session duct' is unnecessary jargon that costs a little 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 mutation tool with no output schema, the description does cover the auth precondition and the fact that a guidance response comes back, which is more than nothing. But an agent still cannot tell what the guidance says, whether optOut exists, or how this differs from memeswap_set_avatar.

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 40% and the description names just three of five parameters (name, emoji, avatar), saying nothing about the required wallet parameter or the optOut flag. With a required-but-undescribed parameter and low schema coverage, the description does not compensate for the gap.

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) plus the underlying endpoint, so an agent knows exactly what the tool mutates. It does not differentiate itself from the sibling memeswap_set_avatar, which appears to overlap on avatar setting, but the core purpose is otherwise unambiguous.

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 gives a real precondition (wallet session bearer or signed profile message) and warns that MCP cannot sign, which implies the tool is effectively inert/gated. However it never names alternatives such as memeswap_set_avatar or the session/message siblings that would establish the prerequisite, so the agent is left to infer the workflow.

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