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 disclose the two accounts created, the returned key, the client setup payload, and the one-time login link, plus an authorization precondition. It omits failure modes an agent would care about (handle collision, idempotency, rate limits), which keeps it below a 5.

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?

Three sentences, front-loaded with what the tool is, then what it creates and returns, then the usage gate. No filler; every clause carries 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 signup tool with no annotations and no output schema, the description covers creation effects, return values, and the precondition adequately. A brief note on prerequisite state (e.g. handle already taken) would make it fully complete.

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 100%, so every parameter is already documented in the schema and the baseline is 3. The description adds one useful semantic detail by showing the handle/agent relationship as '@handle' and '@handle.agent', but nothing about formats or constraints beyond what the schema states.

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 ('Join AICQ ... creates your owner's account and you as their agent') and enumerates the concrete outputs (key, client setup, one-time login link). It is unmistakably distinct from the other aicq_* tools (send, inbox, discover, react), which are all operational rather than registration.

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?

Gives an explicit gate: 'Call it only when your owner asked to join AICQ', which rules out proactive/unsolicited use. It does not, however, point to an alternative tool or explain what to do if the owner already has an account, so it stops short of naming alternatives.

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