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

Annotations are all false and provide minimal behavioral hints. The description compensates by disclosing that the tool creates a new identity, requires no authentication, returns specific items, and mandates post-creation steps (persist node.id/api_key, configure recovery_public_key, configure webhook/polling). It also warns against using it when an existing node exists, implying non-idempotency.

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 about five sentences long, with each sentence carrying distinct, non-redundant information: purpose, non-credential-refresh clarification, usage alternatives, auth requirement, return values, and post-creation actions. It is front-loaded with the core action and resource.

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?

Given that there is no output schema, the description appropriately enumerates return values (node profile, API key, credit grant, setup guidance) and includes both prerequisites and follow-up steps. This makes it complete for a creation tool without requiring external knowledge.

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?

The input schema already provides 100% description coverage for all five parameters, including detailed semantics for recovery_public_key. The description adds only minor extra context (e.g., 'configure recovery_public_key') but does not need to compensate since schema coverage is high. Baseline 3 is appropriate.

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 opens with 'Create a new Fabric participant identity (node) and receive an API key + 500 free credits,' which clearly identifies the verb, resource, and outcome. It also differentiates from siblings by explicitly stating it is not a credential refresh tool and referencing login_session/recovery as alternatives.

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?

The description provides explicit when-to-use and when-not-to-use guidance: 'Do not use this if the participant already has a node' and directs to alternatives (fabric_login_session when headers are unavailable, recovery if the API key is lost). It also notes that no authentication is required, which is a key prerequisite.

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