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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint=false. The description adds value beyond those by stating 'Never signs, never spends' and disclosing specific flags (CRITICAL for key-changed, revoked for human-only) and the ~1 HBAR balance threshold. It does not cover auth requirements, rate limits, or output format.

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 beginning with the core purpose ('Read-only health check...'), followed by the three checks and flags. It is dense but free of filler, and every clause contributes relevant 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 1-parameter tool with no output schema but full safety annotations, the description enumerates what is checked and what gets flagged, which covers nearly all an agent needs. It stops short of describing the exact return shape, so it is not 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% for the single required parameter vault_account_id, so the schema already defines its meaning. The description adds no parameter syntax or format details beyond the vault context.

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 verb ('health check') and resource ('Agent Vault (Hedera mainnet)'), and enumerates three concrete checks. It does not name or contrast with siblings such as prepare_agent_vault, so it stops short of a 5.

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 phrase 'Read-only health check' implies when to use the tool, but the description never explicitly says when to prefer it over alternatives like prepare_agent_vault or when it is inappropriate. Usage guidance is implied rather than stated.

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