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

Annotations only declare the basic write/non-destructive profile; the description adds the crucial behavioral facts that annotations cannot: the key is shown once, there is no password, the key IS the account, it must be set as a Bearer Authorization header, and losing it forfeits the balance without a recovery channel.

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?

Front-loaded with the primary outcome (creates account, returns key), then the conditional warning, then the lifecycle caveats. Every sentence carries an operational instruction with no filler.

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 no-required-param mutation with no output schema, the description still supplies everything needed: what is returned, how to use it, the irreversibility risk, and the recommended next tools. No material gap remains.

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 both parameters (label, contact_email) are already documented in the schema. The description only indirectly reinforces the email's recovery role via the attach_recovery reference, adding no new parameter-level detail. Baseline 3 applies.

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 ('Creates a new account') plus the distinctive outcome ('returns an API key (pc_live_...)') and the differentiator 'WITHOUT registration forms'. An agent can immediately separate this from siblings like get_account or attach_recovery.

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 when-not rule: do not create a new account if the human already has one, and names the concrete alternatives (website cabinet key, Telegram bot). It also prescribes the likely follow-up actions (attach_recovery, link_telegram) right after creation.

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