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

Annotations already signal a mutating, non-idempotent operation (readOnlyHint=false, idempotentHint=false). The description adds that no API key or wallet is required, which is useful, but it does not disclose side effects (identity creation, key issuance, session unlock, possible earnings implications) or what the unlock means. No contradiction, but the behavioral disclosure is thin.

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 front-loaded sentence with the most actionable fact first (no API key needed). But it packs product names and pricing into the same breath as the instruction, which is noise for an agent deciding how to invoke the tool. It is short, but not as clean or information-dense as it should be.

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 15-parameter registration tool with no required params, the description provides almost none of the context an agent needs: it never says all fields are optional, what a typical registration looks like, or what the response contains (mitigated by an output schema). The 100%-covered schema carries the weight, making this minimally adequate but incomplete.

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 the schema fully documents all 15 optional parameters, which is the baseline for a 3. The description adds no parameter-level guidance (e.g., that {} is valid, or that capability_manifest and endpoint matter), so it neither illuminates nor obscures beyond the schema.

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 a specific action (call register) and its purpose (unlock purchase tools for a named skill), which distinguishes it as an onboarding/registration step. However, it reads more like a promotional call-to-action than a precise tool specification, and it does not clarify that register itself creates an owner/agent identity and returns credentials.

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 explicitly instructs when to call ('call this now', 'No API key needed') and what the call enables ('unlock the purchase tools'). It does not, however, contrast with sibling tools like onboard_start, check_earnings, or get_recommended_action, and it never explains what payload to send, so the when is clear but the how is left to the schema.

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