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

No annotations are supplied, so the description carries the full behavioral burden. It does disclose the per-API-key scoping and the full set of returned fields, which is useful, but it never states that the call is a side-effect-free read, nor anything about auth requirements, rate limits, or cost - relevant given how many mutating siblings exist.

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?

Three short sentences, front-loaded with the 'Who am I?' framing, then the return payload, then the call-ordering advice. Nothing is padded or repeated.

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?

With no parameters, no output schema, and no annotations, the description must supply everything, and it largely does by listing the returned fields and stating the intended call order. The remaining gap is that it never explicitly confirms the call is read-only, which an agent about to run money-moving tools would want to know.

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?

Zero parameters, so the baseline of 4 applies; there is nothing for the description to disambiguate. The implicit parameter is the API key itself, which the description does acknowledge by scoping the returned data 'for this API key.'

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?

Specific verb and resource: it answers 'who am I' for the credential and enumerates exactly what comes back (treasury email, user id, credential kind/scopes, vault summary, policy limits). That enumeration distinguishes it from narrower siblings like get_policy_limits or get_portfolio, which return only one slice of this context.

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 explicit when-to-use guidance: 'Call first to confirm you are on the correct account before money-moving tools,' which ties it to the large family of propose_*/propose_hyperliquid_* mutation tools. It does not state when not to use it or name the narrower alternatives (e.g. get_policy_limits) that would serve after identity is established.

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