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

Beyond the annotations (readOnlyHint=false, destructiveHint=false), the description discloses important behavioral traits: the cost, the need for a dedicated key pair, and that the prerequisite check is free with no charge until registration proceeds. It does not describe failure modes or full return behavior, but it is substantially transparent for a mutation tool.

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 three sentences, front-loaded with the core purpose, and every sentence earns its place: outcome, cost/prerequisite, and usage instruction. No redundant or filler content.

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 registration tool with no output schema, the description covers the essential context: purpose, cost, key requirements, and an initial invocation pattern. It does not describe the exact response shape or error handling, but given the tool's complexity, it is adequately 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?

The schema provides 100% coverage with descriptions for all three parameters, giving a baseline of 3. The description adds meaning beyond the schema by clarifying that hedera_account_id becomes part of the DID and that ed25519_public_key is NOT the Hedera ECDSA key, and that omitting it triggers prerequisite instructions.

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 clearly states the tool's purpose with a specific verb ('Register') and resource ('with Fixatum to get a permanent W3C-compliant DID and a live KYA trust score'). It distinguishes from sibling tools like fixatum_status or fixatum_score by focusing on the registration action and its outcomes.

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 gives clear context: prerequisites (dedicated Ed25519 key pair, not your Hedera account key), cost (100 HBAR), and a concrete usage instruction ('Call with hedera_account_id only to get full prerequisites and key generation instructions'). It doesn't explicitly name alternatives or when not to use, which prevents a perfect score.

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